Custom patient interface and methods for making same

ABSTRACT

A method of manufacturing a patient interface for sealed delivery of a flow of air at a continuously positive pressure with respect to ambient air pressure to an entrance to the patient&#39;s airways includes collecting anthropometric data of a patient&#39;s face. Anticipated considerations are identified from the collected anthropometric data during use of the patient interface. The collected anthropometric data is processed to provide a transformed data set based on the anticipated considerations, the transformed data set corresponding to at least one customised patient interface component. At least one patient interface component is modelled based on the transformed data set.

1 CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional ApplicationNo. 62/020,147 filed Jul. 2, 2014, the contents of which is herebyincorporated by reference in its entirety as if fully set forth herein.

2 BACKGROUND OF THE TECHNOLOGY 2.1 Field of the Technology

The present technology relates to one or more of the detection,diagnosis, treatment, prevention and amelioration of respiratory-relateddisorders. In particular, the present technology relates to medicaldevices or apparatus, and their use.

2.2 Description of the Related Art 2.2.1 Human Respiratory System andits Disorders

The respiratory system of the body facilitates gas exchange. The noseand mouth form the entrance to the airways of a patient.

The airways include a series of branching tubes, which become narrower,shorter and more numerous as they penetrate deeper into the lung. Theprime function of the lung is gas exchange, allowing oxygen to move fromthe air into the venous blood and carbon dioxide to move out. Thetrachea divides into right and left main bronchi, which further divideeventually into terminal bronchioles. The bronchi make up the conductingairways, and do not take part in gas exchange. Further divisions of theairways lead to the respiratory bronchioles, and eventually to thealveoli. The alveolated region of the lung is where the gas exchangetakes place, and is referred to as the respiratory zone. See“Respiratory Physiology”, by John B. West, Lippincott Williams &Wilkins, 9th edition published 2011.

A range of respiratory disorders exist. Certain disorders may becharacterised by particular events, e.g. apneas, hypopneas, andhyperpneas.

Obstructive Sleep Apnea (OSA), a form of Sleep Disordered Breathing(SDB), is characterised by events including occlusion or obstruction ofthe upper air passage during sleep. It results from a combination of anabnormally small upper airway and the normal loss of muscle tone in theregion of the tongue, soft palate and posterior oropharyngeal wallduring sleep. The condition causes the affected patient to stopbreathing for periods typically of 30 to 120 seconds in duration,sometimes 200 to 300 times per night. It often causes excessive daytimesomnolence, and it may cause cardiovascular disease and brain damage.The syndrome is a common disorder, particularly in middle agedoverweight males, although a person affected may have no awareness ofthe problem. See U.S. Pat. No. 4,944,310 (Sullivan).

Cheyne-Stokes Respiration (CSR) is another form of sleep disorderedbreathing. CSR is a disorder of a patient's respiratory controller inwhich there are rhythmic alternating periods of waxing and waningventilation known as CSR cycles. CSR is characterised by repetitivede-oxygenation and re-oxygenation of the arterial blood. It is possiblethat CSR is harmful because of the repetitive hypoxia. In some patientsCSR is associated with repetitive arousal from sleep, which causessevere sleep disruption, increased sympathetic activity, and increasedafterload. See U.S. Pat. No. 6,532,959 (Berthon-Jones).

Obesity Hyperventilation Syndrome (OHS) is defined as the combination ofsevere obesity and awake chronic hypercapnia, in the absence of otherknown causes for hypoventilation. Symptoms include dyspnea, morningheadache and excessive daytime sleepiness.

Chronic Obstructive Pulmonary Disease (COPD) encompasses any of a groupof lower airway diseases that have certain characteristics in common.These include increased resistance to air movement, extended expiratoryphase of respiration, and loss of the normal elasticity of the lung.Examples of COPD are emphysema and chronic bronchitis. COPD is caused bychronic tobacco smoking (primary risk factor), occupational exposures,air pollution and genetic factors. Symptoms include: dyspnea onexertion, chronic cough and sputum production.

Neuromuscular Disease (NMD) is a broad term that encompasses manydiseases and ailments that impair the functioning of the muscles eitherdirectly via intrinsic muscle pathology, or indirectly via nervepathology. Some NMD patients are characterised by progressive muscularimpairment leading to loss of ambulation, being wheelchair-bound,swallowing difficulties, respiratory muscle weakness and, eventually,death from respiratory failure. Neuromuscular disorders can be dividedinto rapidly progressive and slowly progressive: (i) Rapidly progressivedisorders: Characterised by muscle impairment that worsens over monthsand results in death within a few years (e.g. Amyotrophic lateralsclerosis (ALS) and Duchenne muscular dystrophy (DMD) in teenagers);(ii) Variable or slowly progressive disorders: Characterised by muscleimpairment that worsens over years and only mildly reduces lifeexpectancy (e.g. Limb girdle, Facioscapulohumeral and Myotonic musculardystrophy). Symptoms of respiratory failure in NMD include: increasinggeneralised weakness, dysphagia, dyspnea on exertion and at rest,fatigue, sleepiness, morning headache, and difficulties withconcentration and mood changes.

Chest wall disorders are a group of thoracic deformities that result ininefficient coupling between the respiratory muscles and the thoraciccage. The disorders are usually characterised by a restrictive defectand share the potential of long term hypercapnic respiratory failure.Scoliosis and/or kyphoscoliosis may cause severe respiratory failure.Symptoms of respiratory failure include: dyspnea on exertion, peripheraloedema, orthopnea, repeated chest infections, morning headaches,fatigue, poor sleep quality and loss of appetite.

A range of therapies have been used to treat or ameliorate suchconditions. Furthermore, otherwise healthy individuals may takeadvantage of such therapies to prevent respiratory disorders fromarising. However, these have a number of shortcomings.

2.2.2 Therapy

Nasal Continuous Positive Airway Pressure (CPAP) therapy has been usedto treat Obstructive Sleep Apnea (OSA). The hypothesis is thatcontinuous positive airway pressure acts as a pneumatic splint and mayprevent upper airway occlusion by pushing the soft palate and tongueforward and away from the posterior oropharyngeal wall. Treatment of OSAby nasal CPAP therapy may be voluntary, and hence patients may elect notto comply with therapy if they find devices used to provide such therapyone or more of uncomfortable, difficult to use, expensive oraesthetically unappealing.

Non-invasive ventilation (NIV) provides ventilatory support to a patientthrough the upper airways to assist the patient in taking a full breathand/or maintain adequate oxygen levels in the body by doing some or allof the work of breathing. The ventilatory support is provided via apatient interface. NIV has been used to treat CSR, OHS, COPD, MD andChest Wall disorders. In some forms, the comfort and effectiveness ofthese therapies may be improved.

Invasive ventilation (IV) provides ventilatory support to patients thatare no longer able to effectively breathe themselves and may be providedusing a tracheostomy tube. In some forms, the comfort and effectivenessof these therapies may be improved.

2.2.3 Diagnosis and Treatment Systems

These therapies may be provided by a treatment system or device. Systemsand devices may also be used to diagnose a condition without treatingit.

A treatment system may comprise a Respiratory Pressure Therapy Device(RPT device), an air circuit, a humidifier, a patient interface, anddata management.

2.2.3.1 Patient Interface

A patient interface may be used to interface respiratory equipment toits user, for example by providing a flow of air. The flow of air may beprovided via a mask to the nose and/or mouth, a tube to the mouth or atracheostomy tube to the trachea of the user. Depending upon the therapyto be applied, the patient interface may form a seal, e.g. with a faceregion of the patient, to facilitate the delivery of gas at a pressureat sufficient variance with ambient pressure to effect therapy, e.g. apositive pressure of about 10 cmH₂O relative to ambient pressure. Forother forms of therapy, such as the delivery of oxygen, the patientinterface may not include a seal sufficient to facilitate delivery tothe airways of a supply of gas at a positive pressure of about 10 cmH₂O.

The design of a patient interface presents a number of challenges. Theface has a complex three-dimensional shape. The size and shape of nosesvaries considerably between individuals. Since the head includes bone,cartilage and soft tissue, different regions of the face responddifferently to mechanical forces. The jaw or mandible may move relativeto other bones of the skull. The whole head may move during the courseof a period of respiratory therapy.

As a consequence of these challenges, some masks suffer from being oneor more of obtrusive, aesthetically undesirable, costly, poorly fitting,difficult to use, and uncomfortable especially when worn for longperiods of time or when a patient is unfamiliar with a system. Forexample, masks designed solely for aviators, masks designed as part ofpersonal protection equipment (e.g. filter masks), SCUBA masks, or forthe administration of anaesthetics may be tolerable for their originalapplication, but nevertheless such masks may be undesirablyuncomfortable to be worn for extended periods of time, e.g. severalhours. This discomfort may lead to a reduction in patient compliancewith therapy. This is even more so if the mask is to be worn duringsleep.

Nasal CPAP therapy is highly effective to treat certain respiratorydisorders, provided patients comply with therapy. If a mask isuncomfortable, or difficult to use a patient may not comply withtherapy. Since it is often recommended that a patient regularly washtheir mask, if a mask is difficult to clean (e.g. difficult to assembleor disassemble), patients may not clean their mask and this may impacton patient compliance.

While a mask for other applications (e.g. aviators) may not be suitablefor use in treating sleep disordered breathing, a mask designed for usein treating sleep disordered breathing may be suitable for otherapplications.

For these reasons, patient interfaces for delivery of nasal CPAP duringsleep form a distinct field.

2.2.3.1.1 Seal-Forming Portion

Patient interfaces may include a seal-forming portion (also referred toherein as a sealing element). Since it is in direct contact with thepatient's face, the shape and configuration of the seal-forming portioncan have a direct impact the effectiveness and comfort of the patientinterface.

A patient interface may be partly characterised according to the designintent of where the seal-forming portion is to engage with the face inuse. In one form of patient interface, a seal-forming portion maycomprise two sub-portions to engage with respective left and rightnares. In one form of patient interface, a seal-forming portion maycomprise a single element that surrounds both nares in use. Such singleelement may be designed to for example overlay an upper lip region and anasal bridge region of a face. In one form of patient interface aseal-forming portion may comprise an element that surrounds a mouthregion in use, e.g. by forming a seal on a lower lip region of a face.In one form of patient interface, a seal-forming portion may comprise asingle element that surrounds both nares and a mouth region in use.These different types of patient interfaces may be known by a variety ofnames by their manufacturer including nasal masks, full-face masks,nasal pillows, nasal puffs and oro-nasal masks.

A seal-forming portion that may be effective in one region of apatient's face may be inappropriate in another region, e.g. because ofthe different shape, structure, variability and sensitivity regions ofthe patient's face. For example, a seal on swimming goggles thatoverlays a patient's forehead may not be appropriate to use on apatient's nose.

Certain seal-forming portions may be designed for mass manufacture suchthat one design fits and is comfortable and effective for a wide rangeof different face shapes and sizes. To the extent to which there is amismatch between the shape of the patient's face, and the seal-formingportion of the mass-manufactured patient interface, one or both mustadapt in order for a seal to form.

One type of seal-forming portion extends around the periphery of thepatient interface, and is intended to seal against the user's face whenforce is applied to the patient interface with the seal-forming portionin confronting engagement with the user's face. The seal-forming portionmay include an air or fluid filled cushion, or a moulded or formedsurface of a resilient seal element made of an elastomer such as arubber. With this type of seal-forming portion, if the fit is notadequate, there will be gaps between the seal-forming portion and theface, and additional force will be required to force the patientinterface against the face in order to achieve a seal.

Another type of seal-forming portion incorporates a flap seal of thinmaterial so positioned about the periphery of the mask so as to providea self-sealing action against the face of the user when positivepressure is applied within the mask. Like the previous style of sealforming portion, if the match between the face and the mask is not good,additional force may be required to effect a seal, or the mask mayunintentionally leak. Furthermore, if the shape of the seal-formingportion does not match that of the patient, it may crease or buckle inuse, giving rise to unintentional leaks.

Another type of seal-forming portion may comprise a friction-fitelement, e.g. for insertion into a naris, however some patients findthese uncomfortable.

Another form of seal-forming portion may use adhesive to effect a seal.Some patients may find it inconvenient to constantly apply and remove anadhesive to their face.

A range of patient interface seal-forming portion technologies aredisclosed in the following patent applications, assigned to ResMedLimited: WO 1998/004,310; WO 2006/074,513; WO 2010/135,785.

One form of nasal pillow is found in the Adam Circuit manufactured byPuritan Bennett. Another nasal pillow, or nasal puff is the subject ofU.S. Pat. No. 4,782,832 (Trimble et al.), assigned to Puritan-BennettCorporation.

ResMed Limited has manufactured the following products that incorporatenasal pillows: SWIFT™ nasal pillows mask, SWIFT™ II nasal pillows mask,SWIFT™ LT nasal pillows mask, SWIFT™ FX nasal pillows mask and LIBERTY™full-face mask. The following patent applications, assigned to ResMedLimited, describe nasal pillows masks: International Patent ApplicationWO2004/073,778 (describing amongst other things aspects of ResMed SWIFT™nasal pillows), US Patent Application 2009/0044808 (describing amongstother things aspects of ResMed SWIFT™ LT nasal pillows); InternationalPatent Applications WO 2005/063,328 and WO 2006/130,903 (describingamongst other things aspects of ResMed LIBERTY™ full-face mask);International Patent Application WO 2009/052,560 (describing amongstother things aspects of ResMed SWIFT™ FX nasal pillows).

2.2.3.1.2 Positioning and Stabilising

A seal-forming portion of a patient interface used for positive airpressure therapy is subject to the corresponding force of the airpressure to disrupt a seal. Thus a variety of techniques have been usedto position the seal-forming portion, and to maintain it in sealingrelation with the appropriate portion of the face.

One technique is the use of adhesives. See for example US PatentApplication Publication No. US 2010/0000534. However the use ofadhesives may be uncomfortable for some.

Another technique is the use of one or more straps and stabilisingharnesses. Many such harnesses suffer from being one or more ofill-fitting, bulky, uncomfortable and awkward to use.

2.2.3.1.3 Vent Technologies

Some forms of patient interface systems may include a vent to allow thewashout of exhaled carbon dioxide. The vent may allow a flow of gas froman interior space of the patient interface, e.g., the plenum chamber, toan exterior of the patient interface, e.g., to ambient. The vent maycomprise an orifice and gas may flow through the orifice in use of themask. Many such vents are noisy. Others may become blocked in use andthus provide insufficient washout. Some vents may be disruptive of thesleep of a bed-partner 1100 of the patient 1000, e.g. through noise orfocussed airflow.

ResMed Limited has developed a number of improved mask venttechnologies. See International Patent Application Publication No. WO1998/034,665; International Patent Application Publication No. WO2000/078,381; U.S. Pat. No. 6,581,594; US Patent Application PublicationNo. US 2009/0050156; US Patent Application Publication No. 2009/0044808.

Table of noise of prior masks (ISO 17510-2:2007, 10 cmH2O pressure at 1m)

A- weighted A- sound weighted power sound level pressure dB(A) dB(A)Mask (uncer- (uncer- Year Mask name type tainty) tainty) (approx.)Glue-on (*) nasal 50.9 42.9 1981 ResCare nasal 31.5 23.5 1993 standard(*) ResMed nasal 29.5 21.5 1998 Mirage ™ (*) ResMed nasal 36 (3) 28 (3)2000 UltraMirage ™ ResMed nasal 32 (3) 24 (3) 2002 Mirage Activa ™ResMed nasal 30 (3) 22 (3) 2008 Mirage Micro ™ ResMed nasal 29 (3) 22(3) 2008 Mirage ™ SoftGel ResMed nasal 26 (3) 18 (3) 2010 Mirage ™ FXResMed nasal 37   29   2004 Mirage pillows Swift ™ (*) ResMed nasal 28(3) 20 (3) 2005 Mirage pillows Swift ™ II ResMed nasal 25 (3) 17 (3)2008 Mirage pillows Swift ™ LT ResMed nasal 21 (3) 13 (3) 2014 AirFitP10 pillows ((*) one specimen only, measured using test method specifiedin ISO3744 in CPAP mode at 10 cmH2O) Sound pressure values of a varietyof objects are listed below A-weighted sound Object pressure dB(A) NotesVacuum cleaner: 68 ISO3744 at 1 m Nilfisk Walter distance Broadly LitterHog: B+ Grade Conversational 60 1 m distance speech Average home 50Quiet library 40 Quiet bedroom at 30 night Background in TV 20 studio

2.2.3.1.4 Respiratory Pressure Therapy (RPT) Device

Air pressure generators are known in a range of applications, e.g.industrial-scale ventilation systems. However, air pressure generatorsfor medical applications have particular requirements not fulfilled bymore generalised air pressure generators, such as the reliability, sizeand weight requirements of medical devices. In addition, even devicesdesigned for medical treatment may suffer from shortcomings, pertainingto one or more of: comfort, noise, ease of use, efficacy, size, weight,manufacturability, cost, and reliability.

An example of the special requirements of certain RPT devices isacoustic noise.

Table of noise output levels of prior RPT devices (one specimen only,measured using test method specified in ISO3744 in CPAP mode at 10cmH2O).

A-weighted sound power Year RPT Device name level dB(A) (approx.)C-Series Tango ™ 31.9 2007 C-Series Tango ™ with Humidifier 33.1 2007 S8Escape ™ II 30.5 2005 S8 Escape ™ II with H4i ™ Humidifier 31.1 2005 S9AutoSet ™ 26.5 2010 S9 AutoSet ™ with H5i Humidifier 28.6 2010

One known RPT device used for treating sleep disordered breathing is theS9 Sleep Therapy System, manufactured by ResMed Limited. Another exampleof an RPT device is a ventilator. Ventilators such as the ResMedStellar™ Series of Adult and Paediatric Ventilators may provide supportfor invasive and non-invasive non-dependent ventilation for a range ofpatients for treating a number of conditions such as but not limited toNMD, OHS and COPD.

The ResMed Elisée™ 150 ventilator and ResMed VS III™ ventilator mayprovide support for invasive and non-invasive dependent ventilationsuitable for adult or paediatric patients for treating a number ofconditions. These ventilators provide volumetric and barometricventilation modes with a single or double limb circuit. RPT devicestypically comprise a pressure generator, such as a motor-driven bloweror a compressed gas reservoir, and are configured to supply a flow ofair to the airway of a patient. In some cases, the flow of air may besupplied to the airway of the patient at positive pressure. The outletof the RPT device is connected via an air circuit to a patient interfacesuch as those described above.

2.2.3.1.5 Humidifier

Delivery of a flow of air without humidification may cause drying ofairways. The use of a humidifier with an RPT device and the patientinterface produces humidified gas that minimizes drying of the nasalmucosa and increases patient airway comfort. In addition in coolerclimates, warm air applied generally to the face area in and about thepatient interface is more comfortable than cold air. A range ofartificial humidification devices and systems are known, however theymay not fulfil the specialised requirements of a medical humidifier.

Medical humidifiers are used to increase humidity and/or temperature ofthe flow of air in relation to ambient air when required, typicallywhere the patient may be asleep or resting (e.g. at a hospital). Amedical humidifier for bedside placement may be small. A medicalhumidifier may be configured to only humidify and/or heat the flow ofair delivered to the patient without humidifying and/or heating thepatient's surroundings. Room-based systems (e.g. a sauna, an airconditioner, or an evaporative cooler), for example, may also humidifyair that is breathed in by the patient, however those systems would alsohumidify and/or heat the entire room, which may cause discomfort to theoccupants. Furthermore medical humidifiers may have more stringentsafety constraints than industrial humidifiers

While a number of medical humidifiers are known, they can suffer fromone or more shortcomings. Some medical humidifiers may provideinadequate humidification, some are difficult or inconvenient to use bypatients.

2.2.3.1.6 Mandibular Repositioning

A mandibular repositioning device (MRD) or mandibular advancement device(MAD) is one of the treatment options for sleep apnea and snoring. It isan adjustable oral appliance available from a dentist or other supplierthat holds the lower jaw (mandible) in a forward position during sleep.The MRD is a removable device that a patient inserts into their mouthprior to going to sleep and removes following sleep. Thus, the MRD isnot designed to be worn all of the time. The MRD may be custom made orproduced in a standard form and includes a bite impression portiondesigned to allow fitting to a patient's teeth. This mechanicalprotrusion of the lower jaw expands the space behind the tongue, putstension on the pharyngeal walls to reduce collapse of the airway anddiminishes palate vibration.

In certain examples a mandibular advancement device may comprise anupper splint that is intended to engage with or fit over teeth on theupper jaw or maxilla and a lower splint that is intended to engage withor fit over teeth on the upper jaw or mandible. The upper and lowersplints are connected together laterally via a pair of connecting rods.The pair of connecting rods are fixed symmetrically on the upper splintand on the lower splint.

In such a design the length of the connecting rods is selected such thatwhen the MRD is placed in a patient's mouth the mandible is held in anadvanced position. The length of the connecting rods may be adjusted tochange the level of protrusion of the mandible. A dentist may determinea level of protrusion for the mandible that will determine the length ofthe connecting rods.

Some MRDs are structured to push the mandible forward relative to themaxilla while other MADs, such as the ResMed Narval CC™ MRD are designedto retain the mandible in a forward position. This device also reducesor minimises dental and temporo-mandibular joint (TMJ) side effects.Thus, it is configured to minimises or prevent any movement of one ormore of the teeth.

2.2.3.1.7 Monitoring Systems

Polysomnography (PSG) is a conventional system for diagnosis andprognosis of cardio-pulmonary disorders. PSG typically involves theplacement of 15 to 20 contact sensors on a person in order to recordvarious bodily signals such as electroencephalography (EEG),electrocardiography (ECG), electrooculograpy (EOG), etc. However, whilethey may be suitable for their usual application in a clinical setting,such systems are complicated and potentially expensive, and/or may beuncomfortable or impractical for a patient at home trying to sleep.

The designer of a device may be presented with an infinite number ofchoices to make to design a product or system. Design criteria oftenconflict, meaning that certain design choices are far from routine orinevitable. Furthermore, the comfort and efficacy of certain aspects maybe highly sensitive to small, subtle changes in one or more parameters.

3 BRIEF SUMMARY OF THE TECHNOLOGY

The present technology is directed towards providing medical devicesused in the diagnosis, amelioration, treatment, or prevention ofrespiratory disorders having one or more of improved comfort, cost,efficacy, ease of use and manufacturability.

A first aspect of the present technology relates to apparatus used inthe diagnosis, amelioration, treatment or prevention of a respiratorydisorder.

Another aspect of the present technology relates to methods used in thediagnosis, amelioration, treatment or prevention of a respiratorydisorder.

An aspect of certain forms of the present technology is to providemethods and/or apparatus that improve the compliance with respiratorytherapy.

One form of the present technology comprises customisation of certainelements of a patient interface.

Another aspect of one form of the present technology is the optimisationof a patient interface based on collected data from a patient.

Another aspect of one form of the present technology is the modificationof at least one of a frame, an intermediate structure, a sealing elementor a headgear of a patient interface.

Another aspect of one form of the present technology is manufacture ofcomfortable patient interfaces having superior sealing that are morelikely to be worn by the user to follow a prescribed therapeutic plan.

Another aspect of one form of the present technology is a patientinterface that is moulded or otherwise constructed with a clearlydefined perimeter shape which is intended to complement that of anintended wearer.

An aspect of one form of the present technology is a method ofmanufacturing apparatus.

An aspect of one form of the present technology is a portable RPT devicethat may be carried by a person, e.g. around the home of the person.

An aspect of one form of the present technology is a patient interfacethat may be washed in a home of a patient, e.g. in soapy water, withoutrequiring specialised cleaning equipment. An aspect of one form of thepresent technology is a humidifier tank that may be washed in a home ofa patient, e.g. in soapy water, without requiring specialised cleaningequipment.

Of course, portions of the aspects may form sub-aspects of the presenttechnology. Also, various ones of the sub-aspects and/or aspects may becombined in various manners and also constitute additional aspects orsub-aspects of the present technology.

Other features of the technology will be apparent from consideration ofthe information contained in the following detailed description,abstract, drawings and claims.

4 BRIEF DESCRIPTION OF THE DRAWINGS

The present technology is illustrated by way of example, and not by wayof limitation, in the figures of the accompanying drawings, in whichlike reference numerals refer to similar elements including:

FIG. 1A shows a system including a patient wearing a patient interfacein the form of a nasal pillow;

FIG. 1B shows a system including a patient wearing a patient interfacein the form of a nasal mask;

FIG. 1C shows a system including a patient wearing a patient interfacein the form of a full face mask;

FIG. 1d shows a patient 1000 undergoing polysomnography (PSG);

FIG. 2A shows an overview of a human respiratory system;

FIG. 2B is a schematic diagram of a human upper airway;

FIG. 2C is a front view of a face with several features of surfaceanatomy identified including the lip superior, upper vermilion, lowervermilion, lip inferior, mouth width, endocanthion, a nasal ala,nasolabial sulcus and cheilion. Also indicated are the directionssuperior, inferior, radially inward and radially outward;

FIG. 2D is a side view of a head with several features of surfaceanatomy identified including glabella, sellion, pronasale, subnasale,lip superior, lip inferior, supramenton, nasal ridge, alar crest point,otobasion superior and otobasion inferior. Also indicated are thedirections superior & inferior, and anterior & posterior;

FIG. 2E is a further side view of a head. The approximate locations ofthe Frankfort horizontal and nasolabial angle are indicated. The coronalplane is also indicated;

FIG. 2F shows a base view of a nose with several features identifiedincluding naso-labial sulcus, lip inferior, upper Vermilion, naris,subnasale, columella, pronasale, the major axis of a naris and thesagittal plane;

FIG. 2G shows a side view of the superficial features of a nose;

FIG. 2H shows subcutaneal structures of the nose, including lateralcartilage, septum cartilage, greater alar cartilage, lesser alarcartilage, sesamoid cartilage, nasal bone, epidermis, adipose tissue,frontal process of the maxilla and fibrofatty tissue;

FIG. 2I shows a medial dissection of a nose, approximately severalmillimeters from a sagittal plane, amongst other things showing theseptum cartilage and medial crus of greater alar cartilage;

FIG. 2J shows a front view of the bones of a skull including thefrontal, nasal and zygomatic bones. Nasal concha are indicated, as arethe maxilla, and mandible;

FIG. 2K shows a lateral view of a skull with the outline of the surfaceof a head, as well as several muscles. The following bones are shown:frontal, sphenoid, nasal, zygomatic, maxilla, mandible, parietal,temporal and occipital. The mental protuberance is indicated. Thefollowing muscles are shown: digastricus, masseter, sternocleidomastoidand trapezius;

FIG. 2L shows an anterolateral view of a nose;

FIG. 3A shows a patient interface in the form of a nasal mask inaccordance with one form of the present technology;

FIG. 3B shows an RPT device in accordance with one form of the presenttechnology;

FIG. 3C is a schematic diagram of the pneumatic path of an RPT device inaccordance with one form of the present technology. The directions ofupstream and downstream are indicated;

FIG. 3D is a schematic diagram of the electrical components of an RPTdevice in accordance with one form of the present technology;

FIG. 3E is a schematic diagram of the algorithms implemented in an RPTdevice in accordance with one form of the present technology;

FIG. 3F is a flow chart illustrating a method carried out by the therapyengine module of FIG. 3E in accordance with one form of the presenttechnology;

FIG. 3G shows an isometric view of a humidifier in accordance with oneform of the present technology;

FIG. 3H shows an isometric view of a humidifier in accordance with oneform of the present technology, showing a humidifier reservoir 5110removed from the humidifier reservoir dock 5130;

FIG. 3I shows a model typical breath waveform of a person whilesleeping;

FIG. 3J shows a patient during Non-REM sleep breathing normally over aperiod of about ninety seconds;

FIG. 3K shows polysomnography of a patient before treatment;

FIG. 3L shows patient flow data where the patient is experiencing aseries of total obstructive apneas;

FIG. 3M shows a scaled inspiratory portion of a breath where the patientis experiencing low frequency inspiratory snore;

FIG. 3N shows a scaled inspiratory portion of a breath where the patientis experiencing an example of flattened inspiratory flow limitation;

FIG. 3O shows a scaled inspiratory portion of a breath where the patientis experiencing an example of “mesa” flattened inspiratory flowlimitation;

FIG. 3P shows a scaled inspiratory portion of a breath where the patientis experiencing an example of “panda ears” inspiratory flow limitation;

FIG. 3Q shows a scaled inspiratory portion of a breath where the patientis experiencing an example of “chair” inspiratory flow limitation;

FIG. 3R shows a scaled inspiratory portion of a breath where the patientis experiencing an example of “reverse chair” inspiratory flowlimitation;

FIG. 3S shows a scaled inspiratory portion of a breath where the patientis experiencing an example of “M-shaped” inspiratory flow limitation;

FIG. 3T shows a scaled inspiratory portion of a breath where the patientis experiencing an example of severely “M-shaped” inspiratory flowlimitation;

FIG. 3U shows patient data from a patient with Cheyne-Stokesrespiration;

FIG. 3V shows patient data from a patient with another example ofCheyne-Stokes respiration, using the same three channels as in FIG. 3U;

FIG. 4 is a flowchart summarising the steps of creating a customisedpatient interface;

FIGS. 5, 6 and 7A-B illustrate various methods of acquiring patientdata;

FIGS. 8A-8B illustrate additional methods of acquiring additionalpatient data relating to a deformed state;

FIGS. 8C-8D illustrate methods of acquiring patient data via pressuremapping;

FIG. 9A is a detailed flow chart of the acquisition and data processingsteps of creating a customised patient interface;

FIGS. 9B and 9C illustrate various facial areas of interest where knowntissue properties may be useful;

FIG. 10A illustrates one example of a nose mask that has been modifiedin response to patient feedback;

FIG. 10B illustrates differences in head shape;

FIG. 10C illustrates a system of acquiring patient data and providingseveral mask options to the patient;

FIG. 11 is a schematic illustrating the three components of a mask;

FIGS. 12A-F illustrate several examples of frames and methods forcreating same;

FIGS. 13A-D illustrate examples of intermediate layers that are capableof attaching to a frame, and sealing layers that are capable ofattaching to the intermediate layer;

FIG. 14A shows a cross-sectional view of an example of a mask cushion ofthe present technology taken along line 2-2 of the mask cushionembodiment of FIG. 14B;

FIG. 14B shows an example embodiment of a mask cushion for a nasal mask;

FIGS. 14C-E are cross-sectional views of several embodiments of aremovable mask cushion for a frame assembly with a partial chamber;

FIG. 14F is a cross-sectional view of a still further embodiment of aportion or part of the mask cushion of the present technologyillustrating various filler materials;

FIGS. 14G-H illustrate another embodiment of a removable mask cushionand an example frame assembly with a channel for retaining the maskcushion;

FIGS. 14I-J are illustrations of a cross section of an example maskcushion in a non-compressed state and a compressed state, respectively;

FIGS. 14K-L are cross-sectional views of two cushions having a pluralityof materials disposed in an inner cushion components;

FIGS. 14M-N are examples of a cushion having a plurality of materialsarranged in layers in an inner cushion components;

FIG. 14O is an example of a cushion having a plurality of materialsarranged in layers in an inner cushion components, and ribs forproviding additional rigidity;

FIG. 14P is an example of a cushion having a plurality of materialsarranged in layers in an inner cushion components separated by frangibleseals;

FIGS. 15A-B illustrate one example of headgear associated with apatient's mask;

FIG. 16A illustrates examples of anchoring points associated with apatient's mask;

FIG. 16B illustrates examples of motion transfer throughout componentsof a patient's mask;

FIGS. 16C-D illustrate the location of a patient interface relative to apatient's head in different sleeping positions;

FIGS. 16E and 16F illustrate some possible facial deformations for whicha patient interface may compensate;

FIG. 16G is an top view illustrating the effects of applying an externalforce to a positioning and stabilising structure worn by a patient;

FIGS. 16H-J are several embodiments of positioning and stabilisingstructures for compensating for skin changes;

FIG. 17A illustrates one example of a nare cover;

FIG. 17B is an annotated diagram showing the coverage of the nare coverof FIG. 17A;

FIGS. 17C-E illustrates image capture and geometric modelling used forforming a custom nare cover;

FIGS. 17F, 17G-1, 17H, and 17I illustrate a frame defining a plenumchamber of a nare cover;

FIGS. 17G-2 illustrates a truncated cone for approximating the deadspace of a plenum chamber;

FIG. 17J illustrates the addition of headgear to the frame of FIGS.17F-I;

FIG. 17K shows one embodiment of a seal interface including twolaminated layers;

FIGS. 17L-N illustrate the making and use of a seal interface;

FIGS. 17O-Q illustrates a nare cover;

FIGS. 17R-T illustrates the use of a nare cover;

FIGS. 18A-B illustrate examples of the manufacturing process ofdifferent components of a patient's mask;

FIGS. 18C-D illustrate additional examples of manufacturing processesfor different components of a patient's mask; and

FIGS. 19A-K illustrate several embodiments of customised masks.

5 DETAILED DESCRIPTION OF EXAMPLES OF THE TECHNOLOGY

Before the present technology is described in further detail, it is tobe understood that the technology is not limited to the particularexamples described herein, which may vary. It is also to be understoodthat the terminology used in this disclosure is for the purpose ofdescribing only the particular examples discussed herein, and is notintended to be limiting.

5.1 Treatment Systems

In one form, the present technology comprises an apparatus or device fortreating a respiratory disorder. The apparatus or device may comprise aRPT device 1500 for supplying pressurised respiratory gas, such as air,to the patient 1000 via an air circuit 1600 to a patient interface 3000.

FIG. 1A shows a system including a patient 1000 wearing a patientinterface 3000, in the form of a nasal pillows, receives a supply of airat positive pressure from a RPT device 1500. Air from the RPT device ishumidified in a humidifier 1700, and passes along an air circuit 1600 tothe patient 1000. A bed partner 1100 is also shown.

FIG. 1B shows a system including a patient 1000 wearing a patientinterface 3000, in the form of a nasal mask, receives a supply of air atpositive pressure from a RPT device 1500. Air from the RPT device ishumidified in a humidifier 1700, and passes along an air circuit 1600 tothe patient 1000.

FIG. 1C shows a system including a patient 1000 wearing a patientinterface 3000, in the form of a full-face mask, receives a supply ofair at positive pressure from a RPT device 1500. Air from the RPT deviceis humidified in a humidifier 1700, and passes along an air circuit 1600to the patient 1000.

In one form, the present technology comprises a method for treating arespiratory disorder comprising the step of applying positive pressureto the entrance of the airways of a patient 1000.

In certain embodiments of the present technology, a supply of air atpositive pressure is provided to the nasal passages of the patient viaone or both nares.

In certain embodiments of the present technology, mouth breathing islimited, restricted or prevented.

5.2 Respiratory System and Facial Anatomy

FIG. 2A shows an overview of a human respiratory system including thenasal and oral cavities, the larynx, vocal folds, oesophagus, trachea,bronchus, lung, alveolar sacs, heart and diaphragm.

FIG. 2B shows a view of a human upper airway including the nasal cavity,nasal bone, lateral nasal cartilage, greater alar cartilage, nostril,lip superior, lip inferior, larynx, hard palate, soft palate,oropharynx, tongue, epiglottis, vocal folds, oesophagus and trachea.

FIG. 2C is a front view of a face with several features of surfaceanatomy identified including the lip superior, upper vermilion, lowervermilion, lip inferior, mouth width, endocanthion, a nasal ala,nasolabial sulcus and cheilion. Also indicated are the directionssuperior, inferior, radially inward and radially outward.

FIG. 2D is a side view of a head with several features of surfaceanatomy identified including glabella, sellion, pronasale, subnasale,lip superior, lip inferior, supramenton, nasal ridge, alar crest point,otobasion superior and otobasion inferior. Also indicated are thedirections superior & inferior, and anterior & posterior.

FIG. 2E is a further side view of a head. The approximate locations ofthe Frankfort horizontal and nasolabial angle are indicated. The coronalplane is also indicated.

FIG. 2F shows a base view of a nose with several features identifiedincluding naso-labial sulcus, lip inferior, upper Vermilion, naris,subnasale, columella, pronasale, the major axis of a naris and thesagittal plane.

FIG. 2G shows a side view of the superficial features of a nose.

FIG. 2H shows subcutaneal structures of the nose, including lateralcartilage, septum cartilage, greater alar cartilage, lesser alarcartilage, sesamoid cartilage, nasal bone, epidermis, adipose tissue,frontal process of the maxilla and fibrofatty tissue.

FIG. 2I shows a medial dissection of a nose, approximately severalmillimeters from a sagittal plane, amongst other things showing theseptum cartilage and medial crus of greater alar cartilage.

FIG. 2J shows a front view of the bones of a skull including thefrontal, nasal and zygomatic bones. Nasal concha are indicated, as arethe maxilla, and mandible.

FIG. 2K shows a lateral view of a skull with the outline of the surfaceof a head, as well as several muscles. The following bones are shown:frontal, sphenoid, nasal, zygomatic, maxilla, mandible, parietal,temporal and occipital. The mental protuberance is indicated. Thefollowing muscles are shown: digastricus, masseter, sternocleidomastoidand trapezius.

FIG. 2L shows an anterolateral view of a nose.

5.3 Patient Interface

FIG. 3A shows a patient interface in the form of a nasal mask inaccordance with one form of the present technology. A non-invasivepatient interface 3000 in accordance with one aspect of the presenttechnology comprises the following functional aspects: a seal-formingstructure 3100 (also referred to as a sealing element), a plenum chamber3200, a positioning and stabilising structure 3300 and one form ofconnection port 3600 for connection to air circuit 1600. In some forms afunctional aspect may be provided by one or more physical components. Insome forms, one physical component may provide one or more functionalaspects. In use the seal-forming structure 3100 is arranged to surroundan entrance to the airways of the patient so as to facilitate the supplyof air at positive pressure to the airways.

5.3.1 Seal-Forming Structure 3100

In one form of the present technology, a seal-forming structure 3100provides a seal-forming surface, and may additionally provide acushioning function.

A seal-forming structure 3100 in accordance with the present technologymay be constructed from a soft, flexible, resilient material such assilicone.

In one form the seal-forming portion of the non-invasive patientinterface 3000 comprises a pair of nasal puffs, or nasal pillows, eachnasal puff or nasal pillow being constructed and arranged to form a sealwith a respective naris of the nose of a patient.

Nasal pillows in accordance with an aspect of the present technologyinclude: a frusto-cone, at least a portion of which forms a seal on anunderside of the patient's nose; a stalk, a flexible region on theunderside of the frusto-cone and connecting the frusto-cone to thestalk. In addition, the structure to which the nasal pillow of thepresent technology is connected includes a flexible region adjacent thebase of the stalk. The flexible regions can act in concert to facilitatea universal joint structure that is accommodating of relativemovement—both displacement and angular—of the frusto-cone and thestructure to which the nasal pillow is connected. For example, thefrusto-cone may be axially displaced towards the structure to which thestalk is connected.

In one form the non-invasive patient interface 3000 comprises aseal-forming portion that forms a seal in use on an upper lip region(that is, the lip superior) of the patient's face.

In one form the non-invasive patient interface 3000 comprises aseal-forming portion that forms a seal in use on a chin-region of thepatient's face.

5.3.2 Plenum Chamber 3200

Preferably the plenum chamber 3200 has a perimeter that is shaped to becomplementary to the surface contour of the face of an average person inthe region where a seal will form in use. In use, a marginal edge of theplenum chamber 3200 is positioned in close proximity to an adjacentsurface of the face. Actual contact with the face is provided by theseal-forming structure 3100. Preferably the seal-forming structure 3100extends in use about the entire perimeter of the plenum chamber 3200.

5.3.3 Positioning and Stabilising Structure 3300

Preferably the seal-forming structure 3100 of the patient interface 3000of the present technology is held in sealing position in use by thepositioning and stabilising structure 3300, commonly referred to asheadgear.

5.3.4 Vent 3400

In one form, the patient interface 3000 includes a vent 3400 constructedand arranged to allow for the washout of exhaled carbon dioxide.

One form of vent 3400 in accordance with the present technologycomprises a plurality of holes, for example, about 20 to about 80 holes,or about 40 to about 60 holes, or about 45 to about 55 holes. In someexamples, the vent 3400 is located in the plenum chamber 3200.

5.3.5 Forehead Support 3500

In one form, the patient interface 3000 includes a forehead support3500.

5.3.6 Decoupling Structure(s)

In one form the patient interface 3000 includes at least one decouplingstructure, for example, a swivel 3510 or a ball and socket 3520.

5.3.7 Connection Port 3600

Connection port 3600 allows for connection to the air circuit 1600.

5.3.8 Anti-Asphyxia Valve

In one form, the patient interface 3000 includes an anti-asphyxia valve3800.

5.3.9 Ports

In one form of the present technology, a patient interface 3000 includesone or more ports that allow access to the volume within the plenumchamber 3200. In one form this allows a clinician to supply supplementaloxygen. In one form, this allows for the direct measurement of aproperty of gases within the plenum chamber 3200, such as the pressure.

5.4 RPT Device

An RPT device 40000 in accordance with one aspect of the presenttechnology comprises mechanical and pneumatic components 41000,electrical components 42000 and is configured to execute one or morealgorithms 43000. The RPT device may have an external housing 40100,formed in two parts, an upper portion 40120 and a lower portion 40140.Furthermore, the external housing 40100 may include one or more panel(s)40150. The RPT device 40000 comprises a chassis 40160 that supports oneor more internal components of the RPT device 40000. The RPT device40000 may include a handle 40180.

The pneumatic path of the RPT device 40000 may comprise one or more airpath items, e.g., an inlet air filter 41120, an inlet muffler 41220, apressure generator 41400 capable of supplying air at positive pressure(e.g., a blower 41420), an outlet muffler 41240 and one or moretransducers 42700, such as pressure sensors 42720 and flow rate sensors42740.

One or more of the air path items may be located within a removableunitary structure which will be referred to as a pneumatic block 40200.The pneumatic block 40200 may be located within the external housing40100. In one form a pneumatic block 40200 is supported by, or formed aspart of the chassis 40160.

The RPT device 40000 may have an electrical power supply 42100, one ormore input devices 42200, a central controller 42300, a therapy devicecontroller 42400, a pressure generator 41400, one or more protectioncircuits 42500, memory 42600, transducers 42700, data communicationinterface 42800 and one or more output devices 42900. Electricalcomponents 42000 may be mounted on a single Printed Circuit BoardAssembly (PCBA) 42020. In an alternative form, the RPT device 40000 mayinclude more than one PCBA 42020.

5.4.1 RPT Device Mechanical & Pneumatic Components

An RPT device may comprise one or more of the following components in anintegral unit. In an alternative form, one or more of the followingcomponents may be located as respective separate units.

5.4.1.1 Air Filter(s)

An RPT device in accordance with one form of the present technology mayinclude an air filter 41100, or a plurality of air filters 41100.

In one form, an inlet air filter 41120 is located at the beginning ofthe pneumatic path upstream of a pressure generator 41400. See FIG. 3C.

In one form, an outlet air filter 41140, for example an antibacterialfilter, is located between an outlet of the pneumatic block 40200 and apatient interface 3000. See FIG. 3C.

5.4.1.2 Muffler(s)

In one form of the present technology, an inlet muffler 41220 is locatedin the pneumatic path upstream of a pressure generator 41400. See FIG.3C.

In one form of the present technology, an outlet muffler 41240 islocated in the pneumatic path between the pressure generator 41400 and apatient interface 3000. See FIG. 3C.

5.4.1.3 Pressure Generator 41400

In one form of the present technology, a pressure generator 41400 forproducing a flow, or a supply, of air at positive pressure is acontrollable blower 41420. For example the blower 41420 may include abrushless DC motor 41440 with one or more impellers housed in a volute.The blower may be capable of delivering a supply of air, for example ata rate of up to about 120 litres/minute, at a positive pressure in arange from about 4 cmH2O to about 20 cmH2O, or in other forms up toabout 30 cmH2O. The blower may be as described in any one of thefollowing patents or patent applications the contents of which areincorporated herein by reference in their entirety: U.S. Pat. No.7,866,944; U.S. Pat. No. 8,638,014; U.S. Pat. No. 8,636,479; and PCTPatent Application Publication No. WO 2013/020167.

The pressure generator 41400 is under the control of the therapy devicecontroller 42400.

In other forms, a pressure generator 41400 may be a piston-driven pump,a pressure regulator connected to a high pressure source (e.g.compressed air reservoir), or a bellows.

5.4.1.4 Transducer(s)

Transducers may be internal of the RPT device, or external of the RPTdevice. External transducers may be located for example on or form partof the air circuit, e.g., the patient interface. External transducersmay be in the form of non-contact sensors such as a Doppler radarmovement sensor that transmit or transfer data to the RPT device.

In one form of the present technology, one or more transducers 42700 arelocated upstream and/or downstream of the pressure generator 41400. Theone or more transducers 42700 may be constructed and arranged to measureproperties such as a flow rate, a pressure or a temperature at thatpoint in the pneumatic path.

In one form of the present technology, one or more transducers 42700 maybe located proximate to the patient interface 3000.

In one form, a signal from a transducer 42700 may be filtered, such asby low-pass, high-pass or band-pass filtering.

5.4.1.4.1 Flow Rate Transducer

A flow rate transducer 42740 in accordance with the present technologymay be based on a differential pressure transducer, for example, anSDP600 Series differential pressure transducer from SENSIRION.

In one form, a signal representing a flow rate such as a total flow rateQt from the flow rate transducer 42740 is received by the centralcontroller 42300.

5.4.1.4.2 Pressure Transducer 42720

A pressure transducer 42720 in accordance with the present technology islocated in fluid communication with the pneumatic path. An example of asuitable pressure transducer is a sensor from the HONEYWELL ASDX series.An alternative suitable pressure transducer is a sensor from the NPASeries from GENERAL ELECTRIC.

In one form, a signal from the pressure transducer 42720 is received bythe central controller 42300.

5.4.1.4.3 Motor Speed Transducer

In one form of the present technology a motor speed transducer 42760 isused to determine a rotational velocity of the motor 41440 and/or theblower 41420. A motor speed signal from the motor speed transducer 42760may be provided to the therapy device controller 42400. The motor speedtransducer 42760 may, for example, be a speed sensor, such as a Halleffect sensor.

5.4.1.5 Anti-Spill Back Valve

In one form of the present technology, an anti-spill back valve islocated between the humidifier 50000 and the pneumatic block 40200. Theanti-spill back valve is constructed and arranged to reduce the riskthat water will flow upstream from the humidifier 50000, for example tothe motor 41440.

5.4.1.6 Air Circuit

An air circuit 41700 in accordance with an aspect of the presenttechnology is a conduit or a tube constructed and arranged in use toallow a flow of air to travel between two components such as thepneumatic block 40200 and the patient interface 3000.

In particular, the air circuit 41700 may be in fluid connection with theoutlet of the pneumatic block and the patient interface. The air circuitmay be referred to as an air delivery tube. In some cases there may beseparate limbs of the circuit for inhalation and exhalation. In othercases a single limb is used.

In some forms, the air circuit 41700 may comprise one or more heatingelements configured to heat air in the air circuit, for example tomaintain or raise the temperature of the air. The heating element may bein a form of a heated wire circuit, and may comprise one or moretransducers, such as temperature sensors. In one form, the heated wirecircuit may be helically wound around the axis of the air circuit 41700.The heating element may be in communication with a controller such as acentral controller 42300 or a humidifier controller. One example of anair circuit 41700 comprising a heated wire circuit is described inUnited States Patent Application No. US/2011/0023874, which isincorporated herewithin in its entirety by reference.

5.4.1.7 Oxygen Delivery

In one form of the present technology, supplemental oxygen 41800 isdelivered to one or more points in the pneumatic path, such as upstreamof the pneumatic block 40200, to the air circuit 41700 and/or to thepatient interface 3000.

5.4.2 RPT Device Electrical Components 5.4.2.1 Power Supply

A power supply 42100 may be located internal or external of the externalhousing 40100 of the RPT device 40000.

In one form of the present technology power supply 42100 provideselectrical power to the RPT device 40000 only. In another form of thepresent technology, power supply 42100 provides electrical power to bothRPT device 40000 and humidifier 50000.

5.4.2.2 Input Devices

In one form of the present technology, an RPT device 40000 includes oneor more input devices 42200 in the form of buttons, switches or dials toallow a person to interact with the device. The buttons, switches ordials may be physical devices, or software devices accessible via atouch screen. The buttons, switches or dials may, in one form, bephysically connected to the external housing 40100, or may, in anotherform, be in wireless communication with a receiver that is in electricalconnection to the central controller 42300.

In one form, the input device 42200 may be constructed and arranged toallow a person to select a value and/or a menu option.

5.4.2.3 Central Controller

In one form of the present technology, the central controller 42300 isone or a plurality of processors suitable to control an RPT device40000.

Suitable processors may include an x86 INTEL processor, a processorbased on ARM® Cortex®-M processor from ARM Holdings such as an STM32series microcontroller from ST MICROELECTRONIC. In certain alternativeforms of the present technology, a 32-bit RISC CPU, such as an STR9series microcontroller from ST MICROELECTRONICS or a 16-bit RISC CPUsuch as a processor from the MSP430 family of microcontrollers,manufactured by TEXAS INSTRUMENTS may also be suitable.

In one form of the present technology, the central controller 42300 is adedicated electronic circuit.

In one form, the central controller 42300 is an application-specificintegrated circuit. In another form, the central controller 42300comprises discrete electronic components.

The central controller 42300 may be configured to receive inputsignal(s) from one or more transducers 42700, and one or more inputdevices 42200.

The central controller 42300 may be configured to provide outputsignal(s) to one or more of an output device 42900, a therapy devicecontroller 42400, a data communication interface 42800 and humidifiercontroller.

In some forms of the present technology, the central controller 42300 isconfigured to implement the one or more methodologies described herein,such as the one or more algorithms 43000 expressed as computer programsstored in a non-transitory computer readable storage medium, such asmemory 42600. In some forms of the present technology, the centralcontroller 42300 may be integrated with an RPT device 40000. However, insome forms of the present technology, some methodologies may beperformed by a remotely located device. For example, the remotelylocated device may determine control settings for a ventilator or detectrespiratory related events by analysis of stored data such as from anyof the sensors described herein.

5.4.2.4 Clock

The RPT device 40000 may include a clock 42320 that is connected to thecentral controller 42300.

5.4.2.5 Therapy Device Controller

In one form of the present technology, therapy device controller 42400is a control module 43300 that forms part of the algorithms 43000executed by the central controller 42300.

In one form of the present technology, therapy device controller 42400is a dedicated motor control integrated circuit. For example, in oneform a MC33035 brushless DC motor controller, manufactured by ONSEMI isused.

5.4.2.6 Protection Circuits

The one or more protection circuits 42500 in accordance with the presenttechnology may comprise an electrical protection circuit, a temperatureand/or pressure safety circuit.

5.4.2.7 Memory

In accordance with one form of the present technology the RPT device40000 includes memory 42600, e.g., non-volatile memory. In some forms,memory 42600 may include battery powered static RAM. In some forms,memory 42600 may include volatile RAM.

Memory 42600 may be located on the PCBA 42020. Memory 42600 may be inthe form of EEPROM, or NAND flash.

Additionally or alternatively, RPT device 40000 includes a removableform of memory 42600, for example a memory card made in accordance withthe Secure Digital (SD) standard.

In one form of the present technology, the memory 42600 acts as anon-transitory computer readable storage medium on which is storedcomputer program instructions expressing the one or more methodologiesdescribed herein, such as the one or more algorithms 43000.

5.4.2.8 Data Communication Systems

In one form of the present technology, a data communication interface42800 is provided, and is connected to the central controller 42300.Data communication interface 42800 may be connectable to a remoteexternal communication network 4282 and/or a local externalcommunication network 4284. The remote external communication network4282 may be connectable to a remote external device 4286. The localexternal communication network 4284 may be connectable to a localexternal device 4288.

In one form, data communication interface 42800 is part of the centralcontroller 42300. In another form, data communication interface 42800 isseparate from the central controller 42300, and may comprise anintegrated circuit or a processor.

In one form, remote external communication network 4282 is the Internet.The data communication interface 42800 may use wired communication (e.g.via Ethernet, or optical fibre) or a wireless protocol (e.g. CDMA, GSM,LTE) to connect to the Internet.

In one form, local external communication network 4284 utilises one ormore communication standards, such as Bluetooth, or a consumer infraredprotocol.

In one form, remote external device 4286 is one or more computers, forexample a cluster of networked computers. In one form, remote externaldevice 4286 may be virtual computers, rather than physical computers. Ineither case, such remote external device 4286 may be accessible to anappropriately authorised person such as a clinician.

The local external device 4288 may be a personal computer, mobile phone,tablet or remote control.

5.4.2.9 Output Devices including Optional Display, Alarms

An output device 42900 in accordance with the present technology maytake the form of one or more of a visual, audio and haptic unit. Avisual display may be a Liquid Crystal Display (LCD) or Light EmittingDiode (LED) display.

5.4.2.9.1 Display Driver

A display driver 4292 receives as an input the characters, symbols, orimages intended for display on the display 4294, and converts them tocommands that cause the display 4294 to display those characters,symbols, or images.

5.4.2.9.2 Display

A display 4294 is configured to visually display characters, symbols, orimages in response to commands received from the display driver 4292.For example, the display 4294 may be an eight-segment display, in whichcase the display driver 4292 converts each character or symbol, such asthe figure “0”, to eight logical signals indicating whether the eightrespective segments are to be activated to display a particularcharacter or symbol.

5.4.3 RPT Device Algorithms 5.4.3.1 Pre-Processing Module

A pre-processing module 4310 in accordance with one form of the presenttechnology receives as an input a signal from a transducer 42700, forexample a flow rate transducer 42740 or pressure transducer 42720, andperforms one or more process steps to calculate one or more outputvalues that will be used as an input to another module, for example atherapy engine module 43200.

In one form of the present technology, the output values include theinterface or mask pressure Pm, the respiratory flow rate Qr, and theleak flow rate Ql.

In various forms of the present technology, the pre-processing module4310 comprises one or more of the following algorithms: pressurecompensation 4312, vent flow rate 4314, leak flow rate 4316, andrespiratory flow rate 4318.

5.4.3.1.1 Pressure Compensation

In one form of the present technology, a pressure compensation algorithm4312 receives as an input a signal indicative of the pressure in thepneumatic path proximal to an outlet of the pneumatic block. Thepressure compensation algorithm 4312 estimates the pressure drop throughthe air circuit 41700 and provides as an output an estimated pressure,Pm, in the patient interface 3000.

5.4.3.1.2 Vent Flow Rate Estimation

In one form of the present technology, a vent flow rate calculationalgorithm 4314 receives as an input an estimated pressure, Pm, in thepatient interface 3000 and estimates a vent flow rate of air, Qv, from avent 3400 in a patient interface 3000.

5.4.3.1.3 Leak Flow Rate Estimation

In one form of the present technology, a leak flow rate algorithm 4316receives as an input a total flow rate, Qt, and a vent flow rate Qv, andprovides as an output an estimate of the leak, i.e. leak flow rate, Ql,by calculating an average of the difference between total flow rate Qtand vent flow rate Qv over a period sufficiently long to include severalbreathing cycles, e.g. about 10 seconds.

In one form, the leak flow rate algorithm 4316 receives as an input atotal flow rate Qt, a vent flow rate Qv, and an estimated pressure, Pm,in the patient interface 3000, and provides as an output a leak flowrate Ql, by calculating a leak conductance, and determining a leak flowrate Ql to be a function of leak conductance and pressure, Pm. Leakconductance is calculated as the quotient of low pass filtered non-ventflow rate equal to the difference between total flow rate Qt and ventflow rate Qv, and low pass filtered square root of pressure Pm, wherethe low pass filter time constant has a value sufficiently long toinclude several breathing cycles, e.g. about 10 seconds. The leak flowrate Ql may be calculated as the product of leak conductance and afunction of pressure, Pm.

5.4.3.1.4 Respiratory Flow Rate Estimation

In one form of the present technology, a respiratory flow rate algorithm4318 receives as an input a total flow rate, Qt, a vent flow rate, Qv,and a leak flow rate, Ql, and estimates a respiratory flow rate of air,Qr, to the patient, by subtracting the vent flow rate Qv and the leakflow rate Ql from the total flow rate Qt.

5.4.3.2 Therapy Engine Module

In one form of the present technology, a therapy engine module 43200receives as inputs one or more of a pressure, Pm, in a patient interface3000, and a respiratory flow rate of air to a patient, Qr, and providesas an output one or more therapy parameters.

In one form of the present technology, a therapy parameter is atreatment pressure Pt.

In one form of the present technology, therapy parameters are one ormore of a level of pressure support, and a target ventilation.

In various forms, the therapy engine module 432000 comprises one or moreof the following algorithms: phase determination 43210, waveformdetermination 43220, ventilation determination 43230, inspiratory flowlimitation determination 43240, apnea/hypopnea determination 43250,snore determination 43260, airway patency determination 43270, targetventilation determination 43280, and therapy parameter determination43290.

5.4.3.2.1 Phase Determination

In one form of the present technology, the RPT device 40000 does notdetermine phase.

In one form of the present technology, a phase determination algorithm43210 receives as an input a signal indicative of respiratory flow rate,Qr, and provides as an output a phase Φ of a current breathing cycle ofa patient 1000.

In some forms, known as discrete phase determination, the phase output Φis a discrete variable. One implementation of discrete phasedetermination provides a bi-valued phase output Φ with values of eitherinhalation or exhalation, for example represented as values of 0 and 0.5revolutions respectively, upon detecting the start of spontaneousinhalation and exhalation respectively. RPT devices 40000 that “trigger”and “cycle” effectively perform discrete phase determination, since thetrigger and cycle points are the instants at which the phase changesfrom exhalation to inhalation and from inhalation to exhalation,respectively. In one implementation of bi-valued phase determination,the phase output Φ is determined to have a discrete value of 0 (thereby“triggering” the RPT device 40000) when the respiratory flow rate Qr hasa value that exceeds a positive threshold, and a discrete value of 0.5revolutions (thereby “cycling” the RPT device 40000) when a respiratoryflow rate Qr has a value that is more negative than a negativethreshold.

Another implementation of discrete phase determination provides atri-valued phase output Φ with a value of one of inhalation,mid-inspiratory pause, and exhalation.

In other forms, known as continuous phase determination, the phaseoutput Φ is a continuous variable, for example varying from 0 to 1revolutions, or 0 to 2π radians. The rate of change of continuouslyvalued phase (in revolutions) with respect to time is equal to theinstantaneous breathing rate in breaths per second. RPT devices 40000that perform continuous phase determination may trigger and cycle whenthe continuous phase reaches 0 and 0.5 revolutions, respectively. In oneimplementation of continuous phase determination, a continuous value ofphase Φ is determined using a fuzzy logic analysis of the respiratoryflow rate Qr. A continuous value of phase determined in thisimplementation is often referred to as “fuzzy phase”. In oneimplementation of a fuzzy phase determination algorithm 4321, thefollowing rules are applied to the respiratory flow rate Qr:

1. If the respiratory flow rate is zero and increasing fast then thephase is 0 revolutions.

2. If the respiratory flow rate is large positive and steady then thephase is 0.25 revolutions.

3. If the respiratory flow rate is zero and falling fast, then the phaseis 0.5 revolutions.

4. If the respiratory flow rate is large negative and steady then thephase is 0.75 revolutions.

5. If the respiratory flow rate is zero and steady and the 5-secondlow-pass filtered absolute value of the respiratory flow rate is largethen the phase is 0.9 revolutions.

6. If the respiratory flow rate is positive and the phase is expiratory,then the phase is 0 revolutions.

7. If the respiratory flow rate is negative and the phase isinspiratory, then the phase is 0.5 revolutions.

8. If the 5-second low-pass filtered absolute value of the respiratoryflow rate is large, the phase is increasing at a steady rate equal tothe patient's breathing rate, low-pass filtered with a time constant of20 seconds.

The output of each rule may be represented as a vector whose phase isthe result of the rule and whose magnitude is the fuzzy extent to whichthe rule is true. The fuzzy extent to which the respiratory flow rate is“large”, “steady”, etc. is determined with suitable membershipfunctions. The results of the rules, represented as vectors, are thencombined by some function such as taking the centroid. In such acombination, the rules may be equally weighted, or differently weighted.

In another implementation of continuous phase determination that isindependent of the respiratory flow rate Qr, the phase Φ is determinedas the half the proportion of the inhalation time Ti that has elapsedsince the previous trigger instant, or 0.5 revolutions plus half theproportion of the exhalation time Te that has elapsed since the previouscycle instant (whichever was more recent).

5.4.3.2.2 Waveform Determination

In one form of the present technology, the therapy parameterdetermination algorithm 43290 provides an approximately constanttreatment pressure throughout a respiratory cycle of a patient.

In others form of the present technology, the therapy parameterdetermination algorithm 43290 controls the pressure generator 41400 toprovide a treatment pressure Pt that varies throughout a respiratorycycle of a patient according to a waveform template.

In one form of the present technology, a waveform determinationalgorithm 43220 provides a waveform template Π(Φ) with values in therange [0, 1] on the domain of phase values Φ provided by the phasedetermination algorithm 43210 to be used by the therapy parameterdetermination algorithm 43290.

In one form, suitable for either discrete or continuously-valued phase,the waveform template Π(Φ) is a square-wave template, having a value of1 for values of phase up to and including 0.5 revolutions, and a valueof 0 for values of phase above 0.5 revolutions. In one form, suitablefor continuously-valued phase, the waveform template Π(Φ) comprises twosmoothly curved portions, namely a smoothly curved (e.g. raised cosine)rise from 0 to 1 for values of phase up to 0.5 revolutions, and asmoothly curved (e.g. exponential) decay from 1 to 0 for values of phaseabove 0.5 revolutions.

In some forms of the present technology, the waveform determinationalgorithm 43220 selects a waveform template Π(Φ) from a library ofwaveform templates, dependent on a setting of the RPT device. In otherforms, the waveform determination algorithm 43220 instantiates awaveform template Π(Φ) from a generic waveform template using one ormore parameters (e.g. time constant of an exponentially curved portion)that are dependent on a current state of the patient 1000.

The predetermined waveform template Π(Φ) may be provided as a lookuptable of values Π as a function of phase values Φ. This approach isparticularly suitable when the phase determination algorithm 43210returns discrete values of phase such as 0 for inhalation and 0.5 forexhalation. This approach may also be used when the phase determinationalgorithm 43210 returns a continuously-valued phase Φ.

5.4.3.2.3 Ventilation Determination

In one form of the present technology, a ventilation determinationalgorithm 43230 receives an input a respiratory flow rate Qr, anddetermines a measure indicative of current patient ventilation, Vent.

In some implementations, the ventilation determination algorithm 43230determines a measure of ventilation Vent that is an estimate of actualpatient ventilation. One such implementation is to take half theabsolute value of respiratory flow rate, Qr, optionally filtered bylow-pass filter such as a second order Bessel low-pass filter with acorner frequency of 0.11 Hz.

In other implementations, the ventilation determination algorithm 43230determines a measure of ventilation Vent that is broadly proportional toactual patient ventilation. One such implementation estimates peakrespiratory flow rate Qpeak over the inspiratory portion of the cycle.This and many other procedures involving sampling the respiratory flowrate Qr produce measures which are broadly proportional to ventilation,provided the flow rate waveform shape does not vary very much (here, theshape of two breaths is taken to be similar when the flow rate waveformsof the breaths normalised in time and amplitude are similar). Somesimple examples include the median positive respiratory flow rate, themedian of the absolute value of respiratory flow rate, and the standarddeviation of flow rate. Arbitrary linear combinations of arbitrary orderstatistics of the absolute value of respiratory flow rate using positivecoefficients, and even some using both positive and negativecoefficients, are approximately proportional to ventilation. Anotherexample is the mean of the respiratory flow rate in the middle Kproportion (by time) of the inspiratory portion, where 0<K<1. There isan arbitrarily large number of measures that are exactly proportional toventilation if the flow rate shape is constant.

5.4.3.2.4 Determination of Inspiratory Flow Limitation

In one form of the present technology, the central controller 42300executes one or more algorithms 43240 for the detection of inspiratoryflow limitation.

In one form, the algorithm 43240 receives as an input a respiratory flowrate signal Qr and provides as an output a metric of the extent to whichthe inspiratory portion of the breath exhibits inspiratory flowlimitation.

In one form of the present technology, the inspiratory portion of eachbreath is identified by a zero-crossing detector. A number of evenlyspaced points (for example, sixty-five), representing points in time,are interpolated by an interpolator along the inspiratory flow rate-timecurve for each breath. The curve described by the points is then scaledby a scaler to have unity length (duration/period) and unity area toremove the effects of changing breathing rate and depth. The scaledbreaths are then compared in a comparator with a pre-stored templaterepresenting a normal unobstructed breath, similar to the inspiratoryportion of the breath shown in FIG. 31. Breaths deviating by more than aspecified threshold (typically 1 scaled unit) at any time during theinspiration from this template, such as those due to coughs, sighs,swallows and hiccups, as determined by a test element, are rejected. Fornon-rejected data, a moving average of the first such scaled point iscalculated by the central controller 42300 for the preceding severalinspiratory events. This is repeated over the same inspiratory eventsfor the second such point, and so on. Thus, for example, sixty fivescaled data points are generated by the central controller 42300, andrepresent a moving average of the preceding several inspiratory events,e.g., three events. The moving average of continuously updated values ofthe (e.g., sixty five) points are hereinafter called the “scaled flowrate” designated as Qs(t). Alternatively, a single inspiratory event canbe utilised rather than a moving average.

From the scaled flow rate, two shape factors relating to thedetermination of partial obstruction may be calculated.

Shape factor 1 is the ratio of the mean of the middle (e.g. thirty-two)scaled flow rate points to the mean overall (e.g. sixty-five) scaledflow rate points. Where this ratio is in excess of unity, the breathwill be taken to be normal. Where the ratio is unity or less, the breathwill be taken to be obstructed. A ratio of about 1.17 is taken as athreshold between partially obstructed and unobstructed breathing, andequates to a degree of obstruction that would permit maintenance ofadequate oxygenation in a typical patient.

Shape factor 2 is calculated as the RMS deviation from unit scaled flowrate, taken over the middle (e.g. thirty two) points. An RMS deviationof about 0.2 units is taken to be normal. An RMS deviation of zero istaken to be a totally flow-limited breath. The closer the RMS deviationto zero, the breath will be taken to be more flow limited.

Shape factors 1 and 2 may be used as alternatives, or in combination. Inother forms of the present technology, the number of sampled points,breaths and middle points may differ from those described above.Furthermore, the threshold values can other than those described.

5.4.3.2.5 Determination of Apneas and Hypopneas

In one form of the present technology, the central controller 42300executes one or more algorithms 43250 for the determination of thepresence of apneas and/or hypopneas.

The one or more algorithms 43250 receive as an input a respiratory flowrate signal Qr and provide as an output a flag that indicates that anapnea or a hypopnea has been detected.

In one form, an apnea will be said to have been detected when a functionof respiratory flow rate Qr falls below a flow rate threshold for apredetermined period of time. The function may determine a peak flowrate, a relatively short-term mean flow rate, or a flow rateintermediate of relatively short-term mean and peak flow rate, forexample an RMS flow rate. The flow rate threshold may be a relativelylong-term measure of flow rate.

In one form, a hypopnea will be said to have been detected when afunction of respiratory flow rate Qr falls below a second flow ratethreshold for a predetermined period of time. The function may determinea peak flow, a relatively short-term mean flow rate, or a flow rateintermediate of relatively short-term mean and peak flow rate, forexample an RMS flow rate. The second flow rate threshold may be arelatively long-term measure of flow rate. The second flow ratethreshold is greater than the flow rate threshold used to detect apneas.

5.4.3.2.6 Determination of Snore

In one form of the present technology, the central controller 42300executes one or more snore algorithms 43260 for the detection of snore.

In one form the snore algorithm 43260 receives as an input a respiratoryflow rate signal Qr and provides as an output a metric of the extent towhich snoring is present.

The algorithm 43260 may comprise the step of determining the intensityof the flow rate signal in the range of 30-300 Hz. Further the algorithm43260 may comprise a step of filtering the respiratory flow rate signalQr to reduce background noise, e.g., the sound of airflow in the systemfrom the blower.

5.4.3.2.7 Determination of Airway Patency

In one form of the present technology, the central controller 42300executes one or more algorithms 43270 for the determination of airwaypatency.

In one form, airway patency algorithm 43270 receives as an input arespiratory flow rate signal Qr, and determines the power of the signalin the frequency range of about 0.75 Hz and about 3 Hz. The presence ofa peak in this frequency range is taken to indicate an open airway. Theabsence of a peak is taken to be an indication of a closed airway.

In one form, the frequency range within which the peak is sought is thefrequency of a small forced oscillation in the treatment pressure Pt. Inone implementation, the forced oscillation is of frequency 2 Hz withamplitude about 1 cmH2O.

In one form, airway patency algorithm 43270 receives as an input arespiratory flow rate signal Qr, and determines the presence or absenceof a cardiogenic signal. The absence of a cardiogenic signal is taken tobe an indication of a closed airway.

5.4.3.2.8 Determination of Target Ventilation

In one form of the present technology, the central controller 42300takes as input the measure of current ventilation, Vent, and executesone or more algorithms 43280 for the determination of a target valueVtgt for the measure of ventilation.

In some forms of the present technology, there is no target ventilationdetermination algorithm 4328, and the target value Vtgt ispredetermined, for example by hard-coding during configuration of theRPT device 40000 or by manual entry through the input device 42200.

In other forms of the present technology, such as adaptiveservo-ventilation (ASV), the target ventilation determination algorithm43280 computes a target value Vtgt from a value Vtyp indicative of thetypical recent ventilation of the patient.

In some forms of adaptive servo-ventilation, the target ventilation Vtgtis computed as a high proportion of, but less than, the typical recentventilation Vtyp. The high proportion in such forms may be in the range(80%, 100%), or (85%, 95%), or (87%, 92%).

In other forms of adaptive servo-ventilation, the target ventilationVtgt is computed as a slightly greater than unity multiple of thetypical recent ventilation Vtyp.

The typical recent ventilation Vtyp is the value around which thedistribution of the measure of current ventilation Vent over multipletime instants over some predetermined timescale tends to cluster, thatis, a measure of the central tendency of the measure of currentventilation over recent history. In one implementation of the targetventilation determination algorithm 4328, the recent history is of theorder of several minutes, but in any case should be longer than thetimescale of Cheyne-Stokes waxing and waning cycles. The targetventilation determination algorithm 43280 may use any of the variety ofwell-known measures of central tendency to determine the typical recentventilation Vtyp from the measure of current ventilation, Vent. One suchmeasure is the output of a low-pass filter on the measure of currentventilation Vent, with time constant equal to one hundred seconds.

5.4.3.2.9 Determination of Therapy Parameters

In some forms of the present technology, the central controller 42300executes one or more algorithms 43290 for the determination of one ormore therapy parameters using the values returned by one or more of theother algorithms in the therapy engine module 43200.

In one form of the present technology, the therapy parameter is aninstantaneous treatment pressure Pt. In one implementation of this form,the therapy parameter determination algorithm 43290 determines thetreatment pressure Pt using the equation

Pt=AΠ(Φ)+P ₀   (1)

where:

A is the pressure support,

Π(Φ) is the waveform template value (in the range 0 to 1) at the currentvalue Φ of phase, and

P₀ is a base pressure.

By determining the treatment pressure Pt using equation (1), the therapyparameter determination algorithm 43290 oscillates the treatmentpressure Pt in synchrony with the spontaneous respiratory effort of thepatient 1000. That is to say, based on the typical waveform templatesΠ(Φ) described above, the therapy parameter determination algorithm43290 increases the treatment pressure Pt at the start of, or during, orinspiration and decreases the treatment pressure Pt at the start of, orduring, expiration. The (non-negative) pressure support A is theamplitude of the oscillation.

If the waveform determination algorithm 43220 provides the waveformtemplate Π(Φ) as a lookup table, the therapy parameter determinationalgorithm 43290 applies equation (1) by locating the nearest lookuptable entry to the current value Φ of phase returned by the phasedetermination algorithm 4321, or by interpolation between the twoentries straddling the current value Φ of phase.

The values of the pressure support A and the base pressure P0 may be setby the therapy parameter determination algorithm 43290 depending on thechosen pressure therapy mode in the manner described below.

5.4.3.3 Therapy Control Module

Therapy control module 43300 in accordance with one aspect of thepresent technology receives as inputs the therapy parameters from thetherapy parameter determination algorithm 43290 of the therapy enginemodule 43200, and controls the pressure generator 41400 to deliver aflow of air in accordance with the therapy parameters.

In one form of the present technology, the therapy parameter is atreatment pressure Pt, and the therapy control module 43300 controls thepressure generator 41400 to deliver a flow of air whose mask pressure Pmat the patient interface 3000 is equal to the treatment pressure Pt.

5.4.3.4 Detection of Fault Conditions

In one form of the present technology, the central controller 42300executes one or more methods for the detection of fault conditions. Thefault conditions detected by the one or more methods may include atleast one of the following:

Power failure (no power, or insufficient power)

Transducer fault detection

Failure to detect the presence of a component

Operating parameters outside recommended ranges (e.g. pressure, flowrate, temperature, PaO2)

Failure of a test alarm to generate a detectable alarm signal.

Upon detection of the fault condition, the corresponding algorithmsignals the presence of the fault by one or more of the following:

Initiation of an audible, visual &/or kinetic (e.g. vibrating) alarm

Sending a message to an external device

Logging of the incident

5.5 Humidifier 5.5.1 Humidifier Overview

In one form of the present technology there is provided a humidifier50000 (e.g. as shown in FIG. 3G) to change the absolute humidity of airor gas for delivery to a patient relative to ambient air. Typically, thehumidifier 50000 is used to increase the absolute humidity and increasethe temperature of the flow of air (relative to ambient air) beforedelivery to the patient's airways.

The humidifier 50000 may comprise a humidifier reservoir, a humidifierinlet to receive a flow of air, and a humidifier outlet to deliver ahumidified flow of air. In some forms, an inlet and an outlet of thehumidifier reservoir may be the humidifier inlet and the humidifieroutlet respectively. The humidifier 50000 may further comprise ahumidifier base, which may be adapted to receive the humidifierreservoir and comprise a heating element.

5.5.2 Humidifier Mechanical Components 5.5.2.1 Water Reservoir

According to one arrangement, the humidifier 50000 may comprise a waterreservoir configured to hold, or retain, a volume of liquid (e.g. water)to be evaporated for humidification of the flow of air. The waterreservoir may be configured to hold a predetermined maximum volume ofwater in order to provide adequate humidification for at least theduration of a respiratory therapy session, such as one evening of sleep.Typically, the reservoir is configured to hold several hundredmillilitres of water, e.g. 300 millilitres (ml), 325 ml, 350 ml or 400ml. In other forms, the humidifier 50000 may be configured to receive asupply of water from an external water source such as a building's watersupply system.

According to one aspect, the water reservoir is configured to addhumidity to a flow of air from the RPT device 40000 as the flow of airtravels therethrough. In one form, the water reservoir may be configuredto encourage the flow of air to travel in a tortuous path through thereservoir while in contact with the volume of water therein.

According to one form, the reservoir may be removable from thehumidifier 50000, for example in a lateral direction.

The reservoir may also be configured to discourage egress of liquidtherefrom, such as when the reservoir is displaced and/or rotated fromits normal, working orientation, such as through any apertures and/or inbetween its sub-components. As the flow of air to be humidified by thehumidifier 50000 is typically pressurised, the reservoir may also beconfigured to prevent losses in pneumatic pressure through leak and/orflow impedance.

5.5.2.2 Conductive Portion

According to one arrangement, the reservoir comprises a conductiveportion 51200 configured to allow efficient transfer of heat from theheating element 52400 to the volume of liquid in the reservoir 51100. Inone form, the conductive portion 51200 may be arranged as a plate,although other shapes may also be suitable. All or a part of theconductive portion 51200 may be made of a thermally conductive materialsuch as aluminium (e.g. approximately 2 mm thick, such as 1 mm, 1.5 mm,2.5 mm or 3 mm), another heat conducting metal or some plastics. In somecases, suitable heat conductivity may be achieved with less conductivematerials of suitable geometry.

5.5.2.3 Humidifier Reservoir Dock

In one form, the humidifier 50000 may comprise a humidifier reservoirdock 51300 (as shown in FIG. 3H) configured to receive the humidifierreservoir 51100. In some arrangements, the humidifier reservoir dock51300 may comprise a locking feature such as a locking lever 51350configured to retain the reservoir 51100 in the reservoir dock 51300.

5.5.2.4 Water Level Indicator

The humidifier reservoir 51100 may comprise a water level indicator51500 as shown in FIG. 3G-3H. In some forms, the water level indicator51500 may provide one or more indications to a user such as the patient1000 or a care giver regarding a quantity of the volume of water in thehumidifier reservoir 51100. The one or more indications provided by thewater level indicator 51500 may include an indication of a maximum,predetermined volume of water, any portions thereof, such as 25%, 50% or75% or volumes such as 200 ml, 300 ml or 400 ml.

5.5.3 Humidifier Electrical & Thermal Components

The humidifier 50000 may comprise a number of electrical and/or thermalcomponents such as those listed below.

5.5.3.1 Humidifier Transducer(s)

The humidifier 50000 may comprise one or more humidifier transducers(sensors) 52100 instead of, or in addition to, transducers 42700described above. Humidifier transducers 52100 may include one or more ofan air pressure sensor 52120, an air flow rate transducer 52140, atemperature sensor 52160, or a humidity sensor 52180 as shown in FIG. 5c. A humidifier transducer 52100 may produce one or more output signalswhich may be communicated to a controller such as the central controller42300 and/or the humidifier controller 52500. In some forms, ahumidifier transducer may be located externally to the humidifier 50000(such as in the air circuit 41700) while communicating the output signalto the controller.

5.5.3.1.1 Pressure Transducer

One or more pressure transducers 52120 may be provided to the humidifier50000 in addition to, or instead of, a pressure transducer 42720provided in the RPT device 40000.

5.5.3.1.2 Flow Rate Transducer

One or more flow rate transducers 52140 may be provided to thehumidifier 50000 in addition to, or instead of, a flow rate transducer42740 provided in the RPT device 40000.

5.5.3.1.3 Temperature Transducer

The humidifier 50000 may comprise one or more temperature transducers52160. The one or more temperature transducers 52160 may be configuredto measure one or more temperatures such as of the heating element 52400and/or of the flow of air downstream of the humidifier outlet 50040. Insome forms, the humidifier 50000 may further comprise a temperaturesensor 5216 to detect the temperature of the ambient air.

5.5.3.1.4 Humidity Transducer

In one form, the humidifier 50000 may comprise one or more humiditysensors 52180 to detect a humidity of a gas, such as the ambient air.The humidity sensor 52180 may be placed towards the humidifier outlet50040 in some forms to measure a humidity of the gas delivered from thehumidifier 50000. The humidity sensor may be an absolute humidity sensoror a relative humidity sensor.

5.5.3.2 Heating Element

A heating element 52400 may be provided to the humidifier 50000 in somecases to provide a heat input to one or more of the volume of water inthe humidifier reservoir 51100 and/or to the flow of air. The heatingelement 52400 may comprise a heat generating component such as anelectrically resistive heating track. One suitable example of a heatingelement 52400 is a layered heating element such as one described in thePCT Patent Application Publication No. WO 2012/171072, which isincorporated herewith by reference in its entirety.

In some forms, the heating element 52400 may be provided in thehumidifier base 50060 where heat may be provided to the humidifierreservoir 51100 primarily by conduction as shown in FIG. 3H.

5.5.3.3 Humidifier Controller

According to one arrangement of the present technology, a humidifier50000 may comprise a humidifier controller 52500. In one form, thehumidifier controller 52500 may be a part of the central controller42300. In another form, the humidifier controller 52500 may be aseparate controller, which may be in communication with the centralcontroller 42300.

In one form, the humidifier controller 52500 may receive as inputsmeasures of characteristics (such as temperature, humidity, pressureand/or flow rate), for example of the flow of air, the water in thereservoir 51100 and/or the humidifier 50000. The humidifier controller52500 may also be configured to execute or implement humidifieralgorithms and/or deliver one or more output signals.

Humidifier controller may comprise one or more controllers, such as acentral humidifier controller 52510, a heated air circuit controller52540 configured to control the temperature of a heated air circuit41710 and/or a heating element controller 52520 configured to controlthe temperature of a heating element 52400.

5.6 Breathing Waveforms

FIG. 3I shows a model typical breath waveform of a person whilesleeping. The horizontal axis is time, and the vertical axis isrespiratory flow rate. While the parameter values may vary, a typicalbreath may have the following approximate values: tidal volume, Vt, 0.5L, inhalation time, Ti, 1.6 s, peak inspiratory flow rate, Qpeak, 0.4L/s, exhalation time, Te, 2.4 s, peak expiratory flow rate, Qpeak, −0.5L/s. The total duration of the breath, Ttot, is about 4 s. The persontypically breathes at a rate of about 15 breaths per minute (BPM), withVentilation, Vent, about 7.5 L/minute. A typical duty cycle, the ratioof Ti to Ttot is about 40%.

FIG. 3J shows a patient during Non-REM sleep breathing normally over aperiod of about ninety seconds, with about 34 breaths, being treatedwith Automatic PAP, and the mask pressure being about 11 cmH2O. The topchannel shows oximetry (SpO2), the scale has a range of saturation from90 to 99% in the vertical direction. The patient maintained a saturationof about 95% throughout the period shown. The second channel showsquantitative respiratory airflow, and the scale ranges from −1 to +1 LPSin a vertical direction, and with inspiration positive. Thoracic andabdominal movement are shown in the third and fourth channels.

FIG. 3K shows polysomnography of a patient before treatment. There areeleven signal channels from top to bottom with a 6 minute horizontalspan. The top two channels are both EEG (electoencephalogram) fromdifferent scalp locations. Periodic spikes in the second EEG representcortical arousal and related activity. The third channel down issubmental EMG (electromyogram). Increasing activity around the time ofarousals represents genioglossus recruitment. The fourth & fifthchannels are EOG (electro-oculogram). The sixth channel is anelectrocardiogram. The seventh channel shows pulse oximetry (SpO2) withrepetitive desaturations to below 70% from about 90%. The eighth channelis respiratory airflow using nasal cannula connected to a differentialpressure transducer. Repetitive apneas of 25 to 35 seconds alternatewith 10 to 15 second bursts of recovery breathing coinciding with EEGarousal and increased EMG activity. The ninth channel shows movement ofchest and the tenth shows movement of abdomen. The abdomen shows acrescendo of movement over the length of the apnea leading to thearousal. Both become untidy during the arousal due to gross bodymovement during recovery hyperpnea. The apneas are thereforeobstructive, and the condition is severe. The lowest channel is posture,and in this example it does not show change.

FIG. 3L shows patient flow rate data where the patient is experiencing aseries of total obstructive apneas. The duration of the recording isapproximately 160 seconds. Flow rates range from about +1 L/s to about−1.5 L/s. Each apnea lasts approximately 10-15 s.

FIG. 3M shows a scaled inspiratory portion of a breath where the patientis experiencing low frequency inspiratory snore.

FIG. 3N shows a scaled inspiratory portion of a breath where the patientis experiencing an example of flattened inspiratory flow limitation.

FIG. 3O shows a scaled inspiratory portion of a breath where the patientis experiencing an example of “mesa” flattened inspiratory flowlimitation.

FIG. 3P shows a scaled inspiratory portion of a breath where the patientis experiencing an example of “panda ears” inspiratory flow limitation.

FIG. 3Q shows a scaled inspiratory portion of a breath where the patientis experiencing an example of “chair” inspiratory flow limitation.

FIG. 3R shows a scaled inspiratory portion of a breath where the patientis experiencing an example of “reverse chair” inspiratory flowlimitation.

FIG. 3S shows a scaled inspiratory portion of a breath where the patientis experiencing an example of “M-shaped” inspiratory flow limitation.

FIG. 3T shows a scaled inspiratory portion of a breath where the patientis experiencing an example of severely “M-shaped” inspiratory flowlimitation.

FIG. 3U shows patient data from a patient with Cheyne-Stokesrespiration. There are three channels: oxygen saturation (SpO2); asignal indicative of flow rate; and thoracic movement. The data span sixminutes. The signal representative of flow rate was measured using apressure sensor connected to nasal cannula. The patient exhibits apneasof about 22 seconds and hyperpneas of about 38 seconds. The higherfrequency low amplitude oscillation during apnea is cardiogenic.

FIG. 3V shows patient data from a patient with another example ofCheyne-Stokes respiration, using the same three channels as in FIG. 3U.The data span ten minutes. The patient exhibits hyperpneas of about 30seconds and hypopneas of about 30 seconds.

5.7 Pressure Therapy Modes

Various respiratory pressure therapy modes may be implemented by the RPTdevice 40000 depending on the values of the parameters A and P0 in thetreatment pressure equation (1) used by the therapy parameterdetermination algorithm 43290 in one form of the present technology.

5.7.1 CPAP Therapy

In some implementations of this form of the present technology, thepressure support A is identically zero, so the treatment pressure Pt isidentically equal to the base pressure P0 throughout the respiratorycycle. Such implementations are generally grouped under the heading ofCPAP therapy. In such implementations, there is no need for the therapyengine module 43200 to determine phase Φ or the waveform template Π(Φ).

In CPAP therapy modes, the base pressure P0 may be a constant value thatis prescribed or determined during titration and hard-coded or manuallyentered to the RPT device 40000. This alternative is sometimes referredto as constant CPAP therapy. Alternatively, the therapy parameterdetermination algorithm 43290 may continuously compute the base pressureP0 as a function of indices or measures of sleep disordered breathingreturned by the respective algorithms in the therapy engine module43200, such as one or more of flow limitation, apnea, hypopnea, patency,and snore. This alternative is sometimes referred to as APAP therapy.

FIG. 3F is a flow chart illustrating a method 45000 carried out by thecentral controller 42300 to continuously compute the base pressure P0 aspart of an APAP therapy implementation of the therapy parameterdetermination algorithm 43290, when the pressure support A isidentically zero.

The method 45000 starts at step 45200, at which the central controller42300 compares the measure of the presence of apnea/hypopnea with afirst threshold, and determines whether the measure of the presence ofapnea/hypopnea has exceeded the first threshold for a predeterminedperiod of time, indicating an apnea/hypopnea is occurring. If so, themethod 45000 proceeds to step 45400; otherwise, the method 45000proceeds to step 45300. At step 45400, the central controller 423000compares the measure of airway patency with a second threshold. If themeasure of airway patency exceeds the second threshold, indicating theairway is patent, the detected apnea/hypopnea is deemed central, and themethod 45000 proceeds to step 45600; otherwise, the apnea/hypopnea isdeemed obstructive, and the method 45000 proceeds to step 45500.

At step 45300, the central controller 423000 compares the measure offlow limitation with a third threshold. If the measure of flowlimitation exceeds the third threshold, indicating inspiratory flow islimited, the method 45000 proceeds to step 45500; otherwise, the method45000 proceeds to step 45600.

At step 45500, the central controller 423000 increases the base pressureP0 by a predetermined pressure increment ΔP, provided the resultingtreatment pressure Pt would not exceed a maximum treatment pressurePmax. In one implementation, the predetermined pressure increment ΔP andmaximum treatment pressure Pmax are 1 cmH2O and 25 cmH2O respectively.In other implementations, the pressure increment ΔP can be as low as 0.1cmH2O and as high as 3 cmH2O, or as low as 0.5 cmH2O and as high as 2cmH2O. In other implementations, the maximum treatment pressure Pmax canbe as low as 15 cmH2O and as high as 35 cmH2O, or as low as 20 cmH2O andas high as 30 cmH2O. The method 45000 then returns to step 45200.

At step 45600, the central controller 423000 decreases the base pressureP0 by a decrement, provided the decreased base pressure P0 would notfall below a minimum treatment pressure Pmin. The method 45000 thenreturns to step 45200. In one implementation, the decrement isproportional to the value of P0−Pmin, so that the decrease in P0 to theminimum treatment pressure Pmin in the absence of any detected events isexponential. In one implementation, the constant of proportionality isset such that the time constant τ of the exponential decrease of P0 is60 minutes, and the minimum treatment pressure Pmin is 4 cmH2O. In otherimplementations, the time constant τ could be as low as 1 minute and ashigh as 300 minutes, or as low as 5 minutes and as high as 180 minutes.In other implementations, the minimum treatment pressure Pmin can be aslow as 0 cmH2O and as high as 8 cmH2O, or as low as 2 cmH2O and as highas 6 cmH2O. Alternatively, the decrement in P0 could be predetermined,so the decrease in P0 to the minimum treatment pressure Pmin in theabsence of any detected events is linear.

5.7.2 Pressure Support Ventilation Therapy

In other implementations of this form of the present technology, thevalue of pressure support A in equation (1) may be positive. Suchimplementations are known as pressure support ventilation therapy, andmay be used to treat CSR. In some implementations of pressure supportventilation therapy, known as servo-ventilation, the therapy parameterdetermination algorithm 43290 takes as input the current measure Vent ofventilation and the target value Vtgt of ventilation provided by thetarget ventilation determination algorithm 43280 and continuouslyadjusts the parameters of equation (1) to bring the current measure Ventof ventilation towards the target value Vtgt of ventilation. In adaptiveservo-ventilation (ASV), the target ventilation Vtgt is computed fromthe typical recent ventilation Vtyp, as described above.

In some forms of servo-ventilation, the therapy parameter determinationalgorithm 43290 applies a control methodology to continuously computethe pressure support A so as to bring the current measure Vent ofventilation towards the target ventilation Vtgt. One such controlmethodology is Proportional-Integral (PI) control. In one implementationof PI control, suitable for ASV modes in which a target ventilation Vtgtis set to slightly less than the typical recent ventilation Vtyp, thepressure support is computed as:

A=G∫(Vent−Vtgt)dt   (2)

where G is the gain of the PI control. Larger values of gain G canresult in positive feedback in the therapy engine module 43200. Smallervalues of gain G may permit some residual untreated CSR or central sleepapnea. In some implementations, the gain G is fixed at a predeterminedvalue, such as 0.4 cmH2O/(L/min)/sec. Alternatively, the gain G may bevaried between therapy sessions, starting small and increasing fromsession to session until a value that all but eliminates CSR is reached.Conventional means for retrospectively analysing the parameters of atherapy session to assess the severity of CSR during the therapy sessionmay be employed in such implementations

The value of the pressure support A computed via equation (2) may beclipped to a range defined as [Amin, Amax]. In this implementation, thepressure support A sits by default at the minimum pressure support Aminuntil the measure of current ventilation Vent falls below the targetventilation Vtgt, at which point A starts increasing, only falling backto Amin when Vent exceeds Vtgt once again.

A minimum pressure support Amin of 3 cmH2O is of the order of 50% of thepressure support required to perform all the work of breathing of atypical patient in the steady state. A maximum pressure support Amax of12 cmH2O is approximately double the pressure support required toperform all the work of breathing of a typical patient, and thereforesufficient to support the patient's breathing if they cease making anyefforts, but less than a value that would be uncomfortable or dangerous.

Other servo-ventilation control methodologies that may be applied by thetherapy parameter determination algorithm 43290 include proportional(P), proportional-differential (PD), andproportional-integral-differential (PID).

In pressure support ventilation therapy modes, the base pressure P0 issometimes referred to as EPAP. EPAP may be a constant value that isprescribed or determined during titration and hard-coded or manuallyentered to the RPT device 40000. This alternative is sometimes referredto as fixed-EPAP pressure support ventilation therapy. Alternatively,the therapy parameter determination algorithm 43290 may continuouslycompute the base pressure P0 as a function of indices or measures ofsleep disordered breathing returned by the respective algorithms in thetherapy engine module 43200, such as one or more of flow limitation,apnea, hypopnea, patency, and snore. This alternative is sometimesreferred to as auto-EPAP pressure support ventilation therapy.

5.8 Glossary

For the purposes of the present technology disclosure, in certain formsof the present technology, one or more of the following definitions mayapply. In other forms of the present technology, alternative definitionsmay apply.

5.8.1 General

Air: In certain forms of the present technology, air may be taken tomean atmospheric air, and in other forms of the present technology airmay be taken to mean some other combination of breathable gases, e.g.atmospheric air enriched with oxygen.

Ambient: In certain forms of the present technology, the term ambientwill be taken to mean (i) external of the treatment system or patient,and (ii) immediately surrounding the treatment system or patient.

For example, ambient humidity with respect to a humidifier may be thehumidity of air immediately surrounding the humidifier, e.g. thehumidity in the room where a patient is sleeping. Such ambient humiditymay be different to the humidity outside the room where a patient issleeping.

In another example, ambient pressure may be the pressure immediatelysurrounding or external to the body.

In certain forms, ambient (e.g., acoustic) noise may be considered to bethe background noise level in the room where a patient is located, otherthan for example, noise generated by an RPT device or emanating from amask or patient interface. Ambient noise may be generated by sourcesoutside the room.

Continuous Positive Airway Pressure (CPAP) therapy: CPAP therapy will betaken to mean the application of a supply of air to an entrance to theairways at a pressure that is continuously positive with respect toatmosphere. The pressure may be approximately constant through arespiratory cycle of a patient. In some forms, the pressure at theentrance to the airways will be slightly higher during exhalation, andslightly lower during inhalation. In some forms, the pressure will varybetween different respiratory cycles of the patient, for example, beingincreased in response to detection of indications of partial upperairway obstruction, and decreased in the absence of indications ofpartial upper airway obstruction.

Patient: A person, whether or not they are suffering from a respiratorydisease.

Automatic Positive Airway Pressure (APAP) therapy: CPAP therapy in whichthe treatment pressure is automatically adjustable, e.g. from breath tobreath, between minimum and maximum limits, depending on the presence orabsence of indications of SDB events.

5.8.2 Aspects of the Respiratory Cycle

Apnea: According to some definitions, an apnea is said to have occurredwhen flow falls below a predetermined threshold for a duration, e.g. 10seconds. An obstructive apnea will be said to have occurred when,despite patient effort, some obstruction of the airway does not allowair to flow. A central apnea will be said to have occurred when an apneais detected that is due to a reduction in breathing effort, or theabsence of breathing effort, despite the airway being patent. A mixedapnea occurs when a reduction or absence of breathing effort coincideswith an obstructed airway.

Breathing rate: The rate of spontaneous respiration of a patient,usually measured in breaths per minute.

Duty cycle: The ratio of inhalation time, Ti to total breath time, Ttot.

Effort (breathing): Breathing effort will be said to be the work done bya spontaneously breathing person attempting to breathe.

Expiratory portion of a breathing cycle: The period from the start ofexpiratory flow to the start of inspiratory flow.

Flow limitation: Flow limitation will be taken to be the state ofaffairs in a patient's respiration where an increase in effort by thepatient does not give rise to a corresponding increase in flow. Whereflow limitation occurs during an inspiratory portion of the breathingcycle it may be described as inspiratory flow limitation. Where flowlimitation occurs during an expiratory portion of the breathing cycle itmay be described as expiratory flow limitation.

Types of flow limited inspiratory waveforms:

-   -   (i) Flattened: Having a rise followed by a relatively flat        portion, followed by a fall.    -   (ii) M-shaped: Having two local peaks, one at the leading edge,        and one at the trailing edge, and a relatively flat portion        between the two peaks.    -   (iii) Chair-shaped: Having a single local peak, the peak being        at the leading edge, followed by a relatively flat portion.    -   (iv) Reverse-chair shaped: Having a relatively flat portion        followed by single local peak, the peak being at the trailing        edge.

Hypopnea: Preferably, a hypopnea will be taken to be a reduction inflow, but not a cessation of flow. In one form, a hypopnea may be saidto have occurred when there is a reduction in flow below a thresholdrate for a duration. A central hypopnea will be said to have occurredwhen a hypopnea is detected that is due to a reduction in breathingeffort. In one form in adults, either of the following may be regardedas being hypopneas:

(i) a 30% reduction in patient breathing for at least 10 seconds plus anassociated 4% desaturation; or

(ii) a reduction in patient breathing (but less than 50%) for at least10 seconds, with an associated desaturation of at least 3% or anarousal.

Hyperpnea: An increase in flow to a level higher than normal flow rate.

Inspiratory portion of a breathing cycle: The period from the start ofinspiratory flow to the start of expiratory flow will be taken to be theinspiratory portion of a breathing cycle.

Patency (airway): The degree of the airway being open, or the extent towhich the airway is open. A patent airway is open. Airway patency may bequantified, for example with a value of one (1) being patent, and avalue of zero (0), being closed (obstructed).

Positive End-Expiratory Pressure (PEEP): The pressure above atmospherein the lungs that exists at the end of expiration.

Peak flow rate (Qpeak): The maximum value of flow rate during theinspiratory portion of the respiratory flow waveform.

Respiratory flow rate, airflow rate, patient airflow rate, respiratoryairflow rate (Qr): These synonymous terms may be understood to refer tothe RPT device's estimate of respiratory airflow rate, as opposed to“true respiratory flow” or “true respiratory airflow”, which is theactual respiratory flow rate experienced by the patient, usuallyexpressed in litres per minute.

Tidal volume (Vt): The volume of air inhaled or exhaled during normalbreathing, when extra effort is not applied.

(inhalation) Time (Ti): The duration of the inspiratory portion of therespiratory flow rate waveform.

(exhalation) Time (Te): The duration of the expiratory portion of therespiratory flow rate waveform.

(total) Time (Ttot): The total duration between the start of theinspiratory portion of one respiratory flow rate waveform and the startof the inspiratory portion of the following respiratory flow ratewaveform.

Typical recent ventilation: The value of ventilation around which recentvalues over some predetermined timescale tend to cluster, that is, ameasure of the central tendency of the recent values of ventilation.

Upper airway obstruction (UAO): includes both partial and total upperairway obstruction. This may be associated with a state of flowlimitation, in which the level of flow increases only slightly or mayeven decrease as the pressure difference across the upper airwayincreases (Starling resistor behaviour).

Ventilation (Vent): A measure of the total amount of gas being exchangedby the patient's respiratory system. Measures of ventilation may includeone or both of inspiratory and expiratory flow, per unit time. Whenexpressed as a volume per minute, this quantity is often referred to as“minute ventilation”. Minute ventilation is sometimes given simply as avolume, understood to be the volume per minute.

5.8.3 RPT Device Parameters

Flow rate: The instantaneous volume (or mass) of air delivered per unittime. While flow rate and ventilation have the same dimensions of volumeor mass per unit time, flow rate is measured over a much shorter periodof time. In some cases, a reference to flow rate will be a reference toa scalar quantity, namely a quantity having magnitude only. In othercases, a reference to flow rate will be a reference to a vectorquantity, namely a quantity having both magnitude and direction. Whereit is referred to as a signed quantity, a flow rate may be nominallypositive for the inspiratory portion of a breathing cycle of a patient,and hence negative for the expiratory portion of the breathing cycle ofa patient. Flow rate will be given the symbol Q. ‘Flow rate’ issometimes shortened to simply ‘flow’. Total flow rate, Qt, is the flowrate of air leaving the RPT device. Vent flow rate, Qv, is the flow rateof air leaving a vent to allow washout of exhaled gases. Leak flow rate,Ql, is the flow rate of leak from a patient interface system.Respiratory flow rate, Qr, is the flow rate of air that is received intothe patient's respiratory system.

Leak: The word leak will be taken to be an unintended flow of air. Inone example, leak may occur as the result of an incomplete seal betweena mask and a patient's face. In another example leak may occur in aswivel elbow to the ambient.

Noise, conducted (acoustic): Conducted noise in the present documentrefers to noise which is carried to the patient by the pneumatic path,such as the air circuit and the patient interface as well as the airtherein. In one form, conducted noise may be quantified by measuringsound pressure levels at the end of an air circuit.

Noise, radiated (acoustic): Radiated noise in the present documentrefers to noise which is carried to the patient by the ambient air. Inone form, radiated noise may be quantified by measuring soundpower/pressure levels of the object in question according to ISO 3744.

Noise, vent (acoustic): Vent noise in the present document refers tonoise which is generated by the flow of air through any vents such asvent holes in the patient interface.

Pressure: Force per unit area. Pressure may be measured in a range ofunits, including cmH2O, g-f/cm2, hectopascal. 1 cmH2O is equal to 1g-f/cm2 and is approximately 0.98 hectopascal. In this specification,unless otherwise stated, pressure is given in units of cmH2O. Thepressure in the patient interface is given the symbol Pm, while thetreatment pressure, which represents a target value to be achieved bythe mask pressure Pm at the current instant of time, is given the symbolPt.

Sound Power: The energy per unit time carried by a sound wave. The soundpower is proportional to the square of sound pressure multiplied by thearea of the wavefront. Sound power is usually given in decibels SWL,that is, decibels relative to a reference power, normally taken as 10-12watt.

Sound Pressure: The local deviation from ambient pressure at a giventime instant as a result of a sound wave travelling through a medium.Sound pressure is usually given in decibels SPL, that is, decibelsrelative to a reference pressure, normally taken as 20×10−6 Pascal (Pa),considered the threshold of human hearing.

5.8.4 Terms for Ventilators

Adaptive Servo-Ventilator (ASV): A servo-ventilator that has achangeable, rather than fixed target ventilation. The changeable targetventilation may be learned from some characteristic of the patient, forexample, a respiratory characteristic of the patient.

Backup rate: A parameter of a ventilator that establishes the minimumbreathing rate (typically in number of breaths per minute) that theventilator will deliver to the patient, if not triggered by spontaneousrespiratory effort.

Cycled: The termination of a ventilator's inspiratory phase. When aventilator delivers a breath to a spontaneously breathing patient, atthe end of the inspiratory portion of the breathing cycle, theventilator is said to be cycled to stop delivering the breath.

EPAP: a base pressure, to which a pressure varying within the breath isadded to produce the desired mask pressure which the ventilator willattempt to achieve at a given time.

IPAP: desired mask pressure which the ventilator will attempt to achieveduring the inspiratory portion of the breath.

Pressure support: A number that is indicative of the increase inpressure during ventilator inspiration over that during ventilatorexpiration, and generally means the difference in pressure between themaximum value during inspiration and the minimum value during expiration(e.g., PS=IPAP−EPAP). In some contexts pressure support means thedifference which the ventilator aims to achieve, rather than what itactually achieves.

Servo-ventilator: A ventilator that measures patient ventilation, has atarget ventilation, and which adjusts the level of pressure support tobring the patient ventilation towards the target ventilation.

Spontaneous/Timed (S/T): A mode of a ventilator or other device thatattempts to detect the initiation of a breath of a spontaneouslybreathing patient. If however, the device is unable to detect a breathwithin a predetermined period of time, the device will automaticallyinitiate delivery of the breath.

Swing: Equivalent term to pressure support.

Triggered: When a ventilator delivers a breath of air to a spontaneouslybreathing patient, it is said to be triggered to do so at the initiationof the respiratory portion of the breathing cycle by the patient'sefforts.

Typical recent ventilation: The typical recent ventilation Vtyp is thevalue around which recent measures of ventilation over somepredetermined timescale tend to cluster. For example, a measure of thecentral tendency of the measures of ventilation over recent history maybe a suitable value of a typical recent ventilation.

Ventilator: A mechanical device that provides pressure support to apatient to perform some or all of the work of breathing.

5.9 Relevant Human Anatomy 5.9.1 Anatomy of the Face

Ala: the external outer wall or “wing” of each nostril (plural: alar)

Alare: The most lateral point on the nasal ala.

Alar curvature (or alar crest) point: The most posterior point in thecurved base line of each ala, found in the crease formed by the union ofthe ala with the cheek.

Auricle: The whole external visible part of the ear.

(nose) Bony framework: The bony framework of the nose comprises thenasal bones, the frontal process of the maxillae and the nasal part ofthe frontal bone.

(nose) Cartilaginous framework: The cartilaginous framework of the nosecomprises the septal, lateral, major and minor cartilages.

Columella: the strip of skin that separates the nares and which runsfrom the pronasale to the upper lip.

Columella angle: The angle between the line drawn through the midpointof the nostril aperture and a line drawn perpendicular to the Frankfurthorizontal while intersecting subnasale.

Frankfort horizontal plane: A line extending from the most inferiorpoint of the orbital margin to the left tragion. The tragion is thedeepest point in the notch superior to the tragus of the auricle.

Glabella: Located on the soft tissue, the most prominent point in themidsagittal plane of the forehead.

Lateral nasal cartilage: A generally triangular plate of cartilage. Itssuperior margin is attached to the nasal bone and frontal process of themaxilla, and its inferior margin is connected to the greater alarcartilage.

Greater alar cartilage: A plate of cartilage lying below the lateralnasal cartilage. It is curved around the anterior part of the naris. Itsposterior end is connected to the frontal process of the maxilla by atough fibrous membrane containing three or four minor cartilages of theala.

Nares (Nostrils): Approximately ellipsoidal apertures forming theentrance to the nasal cavity. The singular form of nares is naris(nostril). The nares are separated by the nasal septum.

Naso-labial sulcus or Naso-labial fold: The skin fold or groove thatruns from each side of the nose to the corners of the mouth, separatingthe cheeks from the upper lip.

Naso-labial angle: The angle between the columella and the upper lip,while intersecting subnasale.

Otobasion inferior: The lowest point of attachment of the auricle to theskin of the face.

Otobasion superior: The highest point of attachment of the auricle tothe skin of the face.

Pronasale: the most protruded point or tip of the nose, which can beidentified in lateral view of the rest of the portion of the head.

Philtrum: the midline groove that runs from lower border of the nasalseptum to the top of the lip in the upper lip region.

Pogonion: Located on the soft tissue, the most anterior midpoint of thechin.

Ridge (nasal): The nasal ridge is the midline prominence of the nose,extending from the Sellion to the Pronasale.

Sagittal plane: A vertical plane that passes from anterior (front) toposterior (rear) dividing the body into right and left halves.

Sellion: Located on the soft tissue, the most concave point overlyingthe area of the frontonasal suture.

Septal cartilage (nasal): The nasal septal cartilage forms part of theseptum and divides the front part of the nasal cavity.

Subalare: The point at the lower margin of the alar base, where the alarbase joins with the skin of the superior (upper) lip.

Subnasal point: Located on the soft tissue, the point at which thecolumella merges with the upper lip in the midsagittal plane.

Supramentale: The point of greatest concavity in the midline of thelower lip between labrale inferius and soft tissue pogonion

5.9.2 Anatomy of the Skull

Frontal bone: The frontal bone includes a large vertical portion, thesquama frontalis, corresponding to the region known as the forehead.

Mandible: The mandible forms the lower jaw. The mental protuberance isthe bony protuberance of the jaw that forms the chin.

Maxilla: The maxilla forms the upper jaw and is located above themandible and below the orbits. The frontal process of the maxillaprojects upwards by the side of the nose, and forms part of its lateralboundary.

Nasal bones: The nasal bones are two small oblong bones, varying in sizeand form in different individuals; they are placed side by side at themiddle and upper part of the face, and form, by their junction, the“bridge” of the nose.

Nasion: The intersection of the frontal bone and the two nasal bones, adepressed area directly between the eyes and superior to the bridge ofthe nose.

Occipital bone: The occipital bone is situated at the back and lowerpart of the cranium. It includes an oval aperture, the foramen magnum,through which the cranial cavity communicates with the vertebral canal.The curved plate behind the foramen magnum is the squama occipitalis.

Orbit: The bony cavity in the skull to contain the eyeball.

Parietal bones: The parietal bones are the bones that, when joinedtogether, form the roof and sides of the cranium.

Temporal bones: The temporal bones are situated on the bases and sidesof the skull, and support that part of the face known as the temple.

Zygomatic bones: The face includes two zygomatic bones, located in theupper and lateral parts of the face and forming the prominence of thecheek.

5.9.3 Anatomy of the Respiratory System

Diaphragm: A sheet of muscle that extends across the bottom of the ribcage. The diaphragm separates the thoracic cavity, containing the heart,lungs and ribs, from the abdominal cavity. As the diaphragm contractsthe volume of the thoracic cavity increases and air is drawn into thelungs.

Larynx: The larynx, or voice box houses the vocal folds and connects theinferior part of the pharynx (hypopharynx) with the trachea.

Lungs: The organs of respiration in humans. The conducting zone of thelungs contains the trachea, the bronchi, the bronchioles, and theterminal bronchioles. The respiratory zone contains the respiratorybronchioles, the alveolar ducts, and the alveoli.

Nasal cavity: The nasal cavity (or nasal fossa) is a large air filledspace above and behind the nose in the middle of the face. The nasalcavity is divided in two by a vertical fin called the nasal septum. Onthe sides of the nasal cavity are three horizontal outgrowths callednasal conchae (singular “concha”) or turbinates. To the front of thenasal cavity is the nose, while the back blends, via the choanae, intothe nasopharynx.

Pharynx: The part of the throat situated immediately inferior to (below)the nasal cavity, and superior to the oesophagus and larynx. The pharynxis conventionally divided into three sections: the nasopharynx(epipharynx) (the nasal part of the pharynx), the oropharynx(mesopharynx) (the oral part of the pharynx), and the laryngopharynx(hypopharynx).

5.10 General Terms 5.10.1 Materials

Silicone or Silicone Elastomer: A synthetic rubber. In thisspecification, a reference to silicone is a reference to liquid siliconerubber (LSR) or a compression moulded silicone rubber (CMSR). One formof commercially available LSR is SILASTIC (included in the range ofproducts sold under this trademark), manufactured by Dow Corning.Another manufacturer of LSR is Wacker. Unless otherwise specified to thecontrary, a preferred form of LSR has a Shore A (or Type A) indentationhardness in the range of about 35 to about 45 as measured using AS™D2240.

Polycarbonate: a typically transparent thermoplastic polymer ofBisphenol-A Carbonate.

5.10.2 Aspects of a Patient Interface

Anti-asphyxia valve (AAV): The component or sub-assembly of a masksystem that, by opening to atmosphere in a failsafe manner, reduces therisk of excessive CO₂ rebreathing by a patient.

Elbow: A conduit that directs an axis of flow of air to change directionthrough an angle. In one form, the angle may be approximately 90degrees. In another form, the angle may be less than 90 degrees. Theconduit may have an approximately circular cross-section. In anotherform the conduit may have an oval or rectangular cross-section.

Frame: Frame will be taken to mean a mask structure that bears the loadof tension between two or more points of connection with a headgear. Amask frame may be a non-airtight load bearing structure in the mask.However, some forms of mask frame may also be air-tight.

Headgear: Headgear will be taken to mean a form of positioning andstabilizing structure designed for use on a head. Preferably theheadgear comprises a collection of one or more struts, ties andstiffeners configured to locate and retain a patient interface inposition on a patient's face for delivery of respiratory therapy. Someties are formed of a soft, flexible, elastic material such as alaminated composite of foam and fabric.

Membrane: Membrane will be taken to mean a typically thin element thathas, preferably, substantially no resistance to bending, but hasresistance to being stretched.

Plenum chamber: a mask plenum chamber will be taken to mean a portion ofa patient interface having walls enclosing a volume of space, the volumehaving air therein pressurised above atmospheric pressure in use. Ashell may form part of the walls of a mask plenum chamber.

Seal: The noun form (“a seal”) will be taken to mean a structure orbarrier that intentionally resists the flow of air through the interfaceof two surfaces. The verb form (“to seal”) will be taken to mean toresist a flow of air.

Shell: A shell will be taken to mean a curved two-dimensional structurepreferably having bending, tensile and compressive stiffness, forexample, a portion of a mask that forms a curved structural wall of themask. Preferably, compared to its overall dimensions, it is relativelythin. In some forms, a shell may be faceted. Preferably such walls areairtight, although in some forms they may not be airtight.

Stiffener: A stiffener will be taken to mean a structural componentdesigned to increase the bending resistance of another component in atleast one direction.

Strut: A strut will be taken to be a structural component designed toincrease the compression resistance of another component in at least onedirection.

Swivel: (noun) A subassembly of components configured to rotate about acommon axis, preferably independently, preferably under low torque. Inone form, the swivel may be constructed to rotate through an angle of atleast 360 degrees. In another form, the swivel may be constructed torotate through an angle less than 360 degrees. When used in the contextof an air delivery conduit, the sub-assembly of components preferablycomprises a matched pair of cylindrical conduits. Preferably there islittle or no leak flow of air from the swivel in use.

Tie: A tie will be taken to be a structural component designed to resisttension.

Vent: (noun) the structure that allows an intentional flow of air froman interior of the mask, or conduit to ambient air, e.g. to allowwashout of exhaled gases.

5.10.3 Terms used in Relation to Patient Interface

Curvature (of a surface): A region of a surface having a saddle shape,which curves up in one direction and curves down in a differentdirection, will be said to have a negative curvature. A region of asurface having a dome shape, which curves the same way in two principaldirections, will be said to have a positive curvature. A flat surfacewill be taken to have zero curvature.

Floppy: A quality of a material, structure or composite that is one ormore of:

-   -   Readily conforming to finger pressure.    -   Unable to retain its shape when caused to support its own        weight.    -   Not rigid.    -   Able to be stretched or bent elastically with little effort.

The quality of being floppy may have an associated direction, hence aparticular material, structure or composite may be floppy in a firstdirection, but stiff or rigid in a second direction, for example asecond direction that is orthogonal to the first direction.

Resilient: Able to deform substantially elastically, and to releasesubstantially all of the energy upon unloading, within a relativelyshort period of time such as 1 second.

Rigid: Not readily deforming to finger pressure, and/or the tensions orloads typically encountered when setting up and maintaining a patientinterface in sealing relationship with an entrance to a patient'sairways.

Semi-rigid: means being sufficiently rigid to not substantially distortunder the effects of mechanical forces typically applied during positiveairway pressure therapy.

5.11 Patient Interface Customisation 5.11.1 Customisation Overview

Customised patient interfaces may be manufactured using rapidprototyping manufacturing techniques (e.g. 3D printing). In thefollowing embodiments, customisation may be of the entire patientinterface system or may be of at least one patient interface component(e.g., a seal-forming structure 3100, frame 11001, positioning andstabilising structure 3300, etc.).

Such customisation may provide a personalised experience by forming apatient interface that specifically fits the patient. Better fit mayinclude superior sealing, more comfort during wear, and/or optimisedperformance, for example, by avoiding seal disruptions, as compared toconventional mass produced injection-moulded patient interfaces.

FIG. 4 is a flowchart summarising the general steps of creating acustomised patient interface. Each of these steps will be discussed ingreater detail below. It will be understood that not every step in theflowchart is necessary and that steps may be eliminated or repeated asdesired. Additionally, certain steps indicate alternatives to oneanother.

Patient interface customisation method 4000 generally includes the stepsof data collection 4300, data processing 4400, patient interface design4500, and patient interface manufacturing 4600. As shown, datacollection may include several data collection techniques 4301, 4302,4303, 4304, which may be utilized in concert or as alternatives. Severaloutputs are generated after various steps including: output datapackages 4450, complete patient interface design package 4550, and finalproduct 4700.

5.11.2 Data Collection 4300

A customised patient interface is one that has been optimised eithervisually, as per the patient's preferences, or geometrically optimisedto suit the patient's unique facial construct or a combination of both.In order to create a custom patient interface for each unique individualpatient, collections of data may be collected as shown in FIG. 4.Relaxed state data collection 4301 refers to data, such asthree-dimensional data of the patient's face obtained in a relaxed,undeformed state. Deformed state data collection 4302 refers to datacollected from the patient's face to indicate areas that deflect whenunder the load of a patient interface or other deflections due todifferent patient sleeping positions (e.g., lying on back, side, front,etc.). In addition to patient data relating to geometry, pressure datamay also be gathered via a pressure mapping techniques 4303 to ensureproper sealing of the patient interface during use. User inputs 4304,such as varying user preferences for aesthetic, comfort or functionalitymay also be collected. Each of these data collection techniques areindependently discussed in greater detail below.

5.11.2.1 Relaxed State Data Collection 4301

FIGS. 5-7 illustrate various methods of acquiring patient data.Collected data may include facial data, head data, and/or facial bonedata of a patient and may be collected by a 3D scanner or any type ofscanning device (contactless methods), or by contact methods (memorymaterial, mechanical rods, etc.).

FIG. 5 illustrates one method of data collection that includes laserscanning. Generally, in this method, time-of-flight and triangulationmethods are used to scan 3D surfaces of objects. As shown, a laserscanning system 5000 may include a laser 5001, which directs a laser orlight wave onto an object 5050 (e.g., a patient's head). The reflectedlight then passes through lens 5002 and is collected by sensor 5003,which may include a position sensing detector or a charge coupleddevice. As shown in FIG. 5, a change in distance da corresponds to adistance db at sensor 5003. Thus, after proper calibration, laserscanning system 5000 may be used to capture the 3D surfaces of the face(nose, cheeks, mouth, eyes, teeth, ears, etc.) as well as the generalhead shape. A point cloud of samples on the surfaces from the subject'sface and head may then be created, the point cloud being capable ofreconstruction to regenerate the relevant 3D surfaces (e.g., a surfacerepresenting the patient's forehead). In some examples, a patient mayuse laser scanning system 5000 at a sleep clinic, pharmacy or otherlocations with access to a laser scanner, and the collected data may betransferred to a patient interface designer or patient interfacemanufacturer.

FIG. 6 illustrates another method of data collection that includespassive stereo photogrammetry. In this method, multiple linked cameras6001, 6002 capture multiple still images of the subject 6050 andestimate the three-dimensional coordinates of points on an object.Estimated coordinates may be determined by measurements made in two ormore photographic images taken from different positions from cameras6001, 6002. Common points may then be identified on each image and aline of sight (or ray) may be constructed from the camera location tothe point on the object. The intersection of these rays (triangulation)may help determine the three-dimensional location of the point. Thus,key features on the images are determined and the 3D point cloud may begenerated on display 6003. In use, patients 6050 may take multiplephotos or videos of their head and face (nose, cheeks, mouth, eyes,teeth, ears, etc.) from different angles. These images are thenprocessed to generate the 3D model of the patients head and face. Insome forms, one or more ‘targets’ of predetermined shapes or patternsmay be used as references for the photogrammetry system, for example bytemporarily placing them on the patient while measurements are taken.

Another method of data collection may include white-lightinterferometry, also referred to as white-light scanning. In thismethod, a white light is projected onto a surface of the object which isto be measured, such as a face. A measurement of the resultinginterferometric pattern is obtained by a measuring system (such as acamera), and processed to obtain a three dimensional profile of theobject such as the patient's head and face.

In some examples, remote data collection may be possible. For example,patient 6050 may take his own photos and send hard and/or soft copies tothe designer and/or manufacturer for processing. With propercalibration, the resolution and accuracy of the method is sufficient forthe application in designing custom fit patient interfaces. Thus, quickand efficient collection from patient 6050 is possible via passivestereo photogrammetry.

Additionally, existing technology may be used to provide propercalibration. For example, certain entertainment systems, such as theXbox Kinect, include the ability to take accurate facial scans usingthis technique without the need of further calibration. Thus, softwaremay be provided to enable patients to “plug and play” an Xbox Kinectinto their computer or other processor, follow simple steps to have ascan taken and then sent to a designer and/or manufacturer for furtheranalysis and design.

The previous two methods may be classified as contactless methods ofmeasurement. Contact methods may also be used in data collection aloneor in combination with contactless methods. Contact methods of datacollection may involve physically placing a patient's face against adevice, which plastically deforms to capture a surface. The data typecollected may be a cloud point data set.

FIG. 7A illustrates one example of a contact or tactile data collectionsystem 7000 for data collection. Data collection system 7000 may includethin rods 7001 like a mechanical pin map. Rods 7001 may be coupled tolinear encoders and/or force sensors 7002 capable of measuring thedistance travelled by each rod 7001 and passing the collected data to aprocessor 7003. Also, the encoder or force sensors 7002 may be capableof measuring the resistance force to the movement of the rods 7001.Variations are possible, including substituting a deformable ordeflectable fabric for rods 7001. In further examples, a rod 7001 may beconfigured to measure a pressure applied between the rod 7001 and theface. Furthermore, the rod 7001 may be configured to deform according toa force or pressure between the rod 7001 and the face.

In one form, the rods 7001 may be biased, for example by springs,towards the surface of the face of the patient. The bias may assist inmaintaining engagement between the face of the patient and the rods7001, while preferably the force of the bias is sufficiently small sothat it does not affect the measurement. For example, the biasing forcemay be set so that it is overcome typically after the face is deflectedby 0.1 mm by the rod 7001. In one form, the biasing force of each rod7001 may be approximately 0.5 N, however the biasing force may be variedto suit a particular data collection system 7000, such as a density ofthe rods 7001, diameter of each rod 7001 or a shape of each rod 7001.

Measuring the resistance to the movement of the rods 7001 may helpdetermine whether the face shape is ‘relaxed’ or ‘deformed’. That is,high resistance may indicate that the point on the face has alreadyreached a deformed state, while a low resistance may indicate a relaxedstate. The resistance information may help predict the thickness of theunderlying soft tissue and/or the maximum surface deflection in thatarea. This gives the ability to characterise the properties of the softtissue and therefore may be an input value for custom patient interfaceproduction. Additionally, rods 7001 may be controlled to resist plasticdeformation by mechanical and electrical methods. Mechanical methods mayinclude increasing and decreasing the friction experienced on the rods7001 via contact or encasing the rods 7001 in viscous fluids when theymove. Electrical methods may include software that controls magneticfields or piezoelectric materials resisting the metallic rods moving. Inreverse, the force of the rods 7001 may be supplied and controlled sothat when the rods 7001 are placed onto the face, the rods 7001 deformthe face surfaces, and therefore the deformed state data can becollected.

The rods 7001 may additionally, or alternatively, characterise amechanical property of the face of the patient, such as an elasticmodulus. For instance, a rod 7001 may measure a force (or pressure)between the rod 7001 and the face, as well as the magnitude ofdeflection of the face in a direction of travel of the rod 7001. Usingsuch a method, the rod 7001 would characterise the modulus of the facealong the direction of travel of the rod 7001, which may not be aconstant value. For example, the elastic modulus of the face at zerodeformation may be different to where the face has been depressed by 1mm by the rod 7001, and yet again to where the face has been depressedby 2 mm by the rod 7001. In some forms, a set of relationships (e.g. afunction, a table, or a curve) may be produced using the above method tocharacterise a potentially non-linear modulus of the face in one or moredirections as desired. Such a set of relationships may be then used tomodel a behaviour of the face under load (e.g. using a finite elementmodelling software) as will be described in further detail below.

Each rod 7001 may comprise a patient end configured to accuratelymeasure the characteristic of the patient's face as desired, while notbeing so uncomfortable that it may discourage the patient from using thedata collection system 7000. In one form, the patient end of the rod7001 may comprise a dome shape, or a flat disc shape. The force, orpressure, measured by each rod 7001 may vary according to the particularshape of the patient end of the rod 7001. For example, where a domeshape is used, as the rod 7001 comes in contact with the patient's face,the area in contact with the face (contact area) would be effectively avery small point at the tip of the dome. As the rod 7001 continues totravel and deform the surface of the face, the size of the contact areamay increase until the entire surface of the dome is in contact with theface. Conversely, where a flat shape (e.g. disc) is used, any curvaturepresent on the face of the patient may lead to a point contact.

Preferably, the shape of the patient end of the rod 7001 (e.g. curvatureand radius in case of a dome, or a radius if a flat disc) is such that asize of the contact area is known, or able to be determined, so that anyeffects due to a change in the size of contact area may be taken intoaccount.

In some cases, minimisation of a number of rods 7001 may be desired, forexample to reduce costs of producing the data collection system 7000. Inone example, the rods 7001 may be placed in an array with a varyingdensity to reduce their numbers. The data collection system 7000 maycomprise a higher density of rods 7001 where the resolution ofmeasurement to be obtained is required to be higher, such as in areaswhere a curvature of the face is expected to be greater than in otherareas. For example, rods 7001 may be placed with a higher density inareas of the data collection system 7000 to be placed on the patient'scheek, and with a lower density of rods 7001 around areas of the datacollection system 7000 to be placed on the patient's upper lip.

In one form, the data collection system 7000 may be arranged tocharacterise the face and the head in a single direction, such as byarranging the rods 7001 in the single direction. However, in otherforms, the rods 7001 may be arranged in varying directions in the datacollection system 7000 to characterise the face and the head in aplurality of directions, such as an expected direction of engagementbetween the face and the patient interface cushion in each region. Forexample, the direction of the rods 7001 around the area of the datacollection 7000 for the patient's lower cheek may be different to thedirection of the rods 7001 for the patient's upper cheek, or the nosebridge. In some forms, the data collection system 7000 may comprise aplurality of rods 7001 configured to characterise the same region of theface in different directions. For example, one rod 7001 may characterisea modulus along the anterior/posterior direction, while another rod 7001characterises a modulus in the same location along the left/rightdirection.

In one example, the supplied resistance may mimic patient interfacecontact pressures and CPAP pressures within the patient interface (e.g.2-40 cmH₂O). Thus, the deformed state of a patient's face and head mayalso be captured. Furthermore, by characterising the behaviour of theface and the head as it deforms under load (i.e. pressure/force),customisation of the patient interface may be possible to allow for achange in a pressure provided in the patient interface. In some cases,measurements of a patient's face or head for may be performed prior totitration of the patient to determine an appropriate treatment pressure(or pressure range). In such cases, characterisation of the face and thehead (e.g. elastic modulus) over a range of conditions (such as extentof deformation) may better allow an appropriate customised patientinterface to be produced when the patient is titrated. Contactlessmethods may be performed at a sleep clinic or pharmacy. Alternatively, adevice may be shipped to a patient to collect the data and returned tothe designer after usage.

Additional medical imaging techniques may also be used to capture 3Dimages of the patient's facial and head structure. These may include butare not limited to CT scans, ultrasound and MRI. Thus, the same set ofimages that may have been generated during diagnosis may be used tocompute and provide a 3D surface model of a patient's head and face(nose, cheeks, mouth, eyes, teeth, ears, etc.). Such a method may alsoinclude the added benefit of capturing not only the surfaces, but alsothe underlying soft tissue and bone structure, which may be used tofurther improve the design of the patient's patient interface.

As shown in FIG. 7B, another embodiment of data collection includestaking a cast or creating a mould of the patient's face 7050, capturingtheir individual facial features as an imprint within a cast material.Such an embodiment could use a cast material such as a plaster, athermoset plastic or a room temperature vulcanising silicone. Castmaterial 7060 may be initially malleable such that it is applied to thepatient's face 7050 to form imprint then later solidifies to permanentlystore the individual facial geometry of the patient's face in mould7065. The process of casting the patient's face to form mould 7065 isconsidered a preliminary process.

Once mould 7065 of patient's face 7050 has been created it is scannedusing contactless or contact methods earlier described. If a contactlessmethod is used, a digital image of the patient's face 7050 from mould7065 is captured and recorded using scanner 7070. Alternatively, mould7065 could be used directly within the patient interface manufacturingprocess as a means of delivering/moulding the unique facial features toaspects of the patient interface design. Mould 7065 could be assembledwith other tooling 7075 used to create the common components of thepatient interface to give the custom nature of new or existing patientinterface designs. A part of mould 7065 may be extracted or cut from anentire facial mould, for example, the part corresponding to thepatient's nose. This part is then placed in a tool for manufacture ofthe custom patient interface.

5.11.2.2 Deformed State Data Collection 4302

As discussed above with reference to contact or tactile imaging system,deformed state data collection 4302 may, in some cases, be performedusing the same methods or techniques of the relaxed state datacollection. A face deforming device 8001 may be useful in gathering datafor deformed state data collection 4302. The force applied to the facemay be tuneable.

The method involves placing a rigid or semi-rigid deforming device 8001onto the patient's skin 8050, which mimics the deformation of the facesurfaces during CPAP therapy with a given headgear tension and CPAPpressure. Once deforming device is 8001 is worn, the surfaces are thencaptured with any of the methods described above for relaxed state datacollection. Optionally, deforming device 8001 may be constructed fromtransparent materials to allow visual surface capturing methods(schematically shown by camera 8002) to capture the ‘deformed’ surfacesof the patient's face.

Deforming device 8001 may further include materials, which are easilyidentifiable or contrast with human tissue on medical images (e.g.,radiopaque materials). Thus, on medical images, boundaries between theskin and device may be quickly identified and the deformed 3D surfaceson the patient's skin may be calculated. Deforming device 8001 may bemade available at sleep clinics or sent out the patient to collect thedata and return the device.

Deforming device 8001 may include materials ranging from rigid materialsto silicone cushion softness. The hardness of the material may rangefrom different grades to simulate a patient interface on the patient at1-10N of headgear force and also CPAP pressures of between 5-45 cmH₂O(optimally 10-20 cmH₂O).

As shown in the example in FIG. 8B, deforming device 8010 may be in theform of a pusher or deflector designed to push onto the face atpre-determined locations (e.g., nasal bridge 8051) to deform the skinsurface to simulate patient interface and/or air pressure. Once thedeflector is onto the face, the deformed surfaces 8055 are then capturedwith any of the methods described above for relaxed state datacollection.

The patient intending to wear the customised patient interface will mostlikely wear the patient interface lying down in a supine position. Giventhe effects gravity has on the face varies as a function of the face'salignment to the gravitational pull, it is probable that an indicationof the face's surface geometry in the supine position will be desirable.This may be achieved via a scan while the patient is lying down, usingany of the described techniques. Alternatively, the expected geometry ofthe face may be determined by applying an algorithm to the upright scanof the patient's face, the algorithm may take in to account such factorsas the patient's age, sex, BMI, ethnicity and/or other factors thatimpact the expected magnitude of passive facial movement. Thisprediction algorithm may be performed using physiological modellingsoftware such as ANSYS as will be described in greater detail below.

5.11.2.3 Pressure Mapping 4303

The pressure of a patient interface seal-forming structure 3100 on thepatient may also be measured for the best fit and comfort via a pressuremapping 4303. In one example, a patient interface blank or dummy patientinterface 8020 is worn and a tactile pressure film sensor 8021 isdisposed between dummy patient interface 8020 and the patient's skin8050. Pressure film 8021 may be a generic shape to fit a given patientpopulation (e.g., adult, child, ethnicity, etc.). When dummy patientinterface 8020 is worn, film 8021 may measure a grid of the pressurevalues experienced on the patient's face. In order to ensure an adequateseal around the perimeter of the patient interface, pressure valueswithin a predetermined range may be targeted. Data captured in thisprocess may include the known geometry of dummy patient interface 8020along with a grid of pressure measurements on the patient contactsurface. Such data may be sent to a computer having a processor 8022 andmay be used to generate charts, tables or diagrams such as pressure map8030 from pressure values gathered from this technique.

In some examples, dummy patient interface 8020 may include a genericnasal patient interface shape based on a population, creating a seal onthe patient with relative ease. Dummy patient interface 8020 may furtherhave a soft cushion to mimic a real patient interface on the face. Insome examples, the soft cushion may include a silicone, a foam, a geland other suitable materials.

User preferences and input may also be collected at user input 4304.This may include a variety of data relating to form, function,aesthetic, comfort or other preference and will be discussed in furtherdetail below following the processing of data from relaxed state datacollection 4301, deformed state data collection 4302, and pressuremapping 4303.

5.11.3 Data Processing 4400

The collected patient data from step 4300 may be transforming orprocessed in data processing step 4400 before making a patient interfacefor that patient. Without data processing 4400, a mirror image of ascanned face (superficial topography) may be used to create a patientinterface. Such a patient interface, however, is not necessarily ideal,because certain areas of the sealing region on the face may requiredifferent levels of sealing force, or are more sensitive to tightheadgear pressure, or are more likely to have a leak in that locationdue to complex facial geometry. These finer details relevant toperformance and comfort are accounted for in data processing 4400.

FIG. 9A is a detailed flow chart of the data collection 4300, dataprocessing 4400, and output data packages 4450 of patient interfacecustomisation method 4000.

In one example, the relaxed state geometry data from relaxed state datacollection 4301 may be used to try and provide an indication of thedeformed state geometry if it cannot be directly measured or isunavailable. Simulation software may be used in relaxed data postprocessing 4401 to simulate the deformed state. Examples of suitablesimulation software may include but is not limited to ANSYS whichperforms a transformation from ‘relaxed’ to ‘deformed’ state geometrydata in relaxed data post processing step 4401.

With both the ‘Relaxed’ and ‘Deformed’ states of geometry data, Finiteelement software (such as ANSYS) may be used to calculate approximatepressure values experienced between the patient interface contact areaand the patient's face in simulating experienced pressure 4402.Alternatively, pressure data may be gathered separately via pressuremapping 4303 as discussed above. Thus, from relaxed state datacollection 4301, the deformed geometry may be estimated as well as theexperienced pressure, and the system is capable of providing acustomised patient interface even if one or more of the data collectionsteps are unavailable.

With the measured data, either geometric or pressure data, areas orfeatures on the patient's face, which require special consideration maybe determined and addressed in specific feature processing 4403.Optionally, data from any combination of measurement sources may providea comprehensive model that includes both the geometry and pressure datasets to further the goals of providing comfort, efficacy and complianceof the design.

Additionally, in order to enhance the user experience and increasepatient interaction, patient interface customisation method 4000proposes a platform through which the user has design input into thefinal product. This system may provide user input that ranges from minorto major design control, with or without design input from the designerand/or manufacturer, including but not limited to: aesthetics,mechanical considerations, therapy dependant variables, comfort and sealcharacteristics. This data is gathered in data input 4304 and processedin applying patient preferences 4404 of data processing 4400.

5.11.3.1 Relaxed Data Post Processing 4401

The face is not a static surface. Rather it adapts and changes tointeractions with external conditions, such as forces from a patientinterface, air pressure on the face and gravity. By accounting for theseinteractions, additional benefits are gained in providing the optimumseal and comfort to the patient. Three examples illustrate thisprocessing.

First, since the patient wearing these patient interfaces willexperience CPAP pressure, this knowledge may be used to enhance thecomfort and sealing of the patient interface. Simulation software alongwith known characteristics (e.g. soft tissue properties or elasticmoduli) may help predict the deformations the surfaces of the face willexperience at a particular air pressure within the patient interface.

Tissue properties may be known and gathered for a population relating toany of the following facial locations: supraglabella, glabella, nasion,end of nasal, mid-philtrum, upper lip margin, lower lip margin, chin-lipfold, mental eminence, beneath chin, frontal eminence, supra orbital,lateral glabella, lateral nasal, suborbital, inferior malar, lateralnostril, naso-labial ridge, supra canina, sub canina, mental tubercleant., mid lateral orbit, supraglenoid, zygomatic, lateral, supra-M2,mid-masseter muscle, occlusal line, sub-m2, gonion, and the midmandibular angle.

FIG. 9B illustrates one exemplary embodiment, in which soft tissuethickness is known from anthropometric databases for at least one of thefollowing locations of patient 9000: nasian 9003, end of nasal 9004,mid-philtrum 9005, chin-lip fold 9008, mental eminence 9009, suborbital9015, inferior malar 9016, lateral nostril 9017, naso-labial ridge 9018,supra canina 9019, sub canina 9020. As shown in FIG. 9B, certainlocations such as suborbital 9015, inferior malar 9016, lateral nostril9017, naso-labial ridge 9018, supra canina 9019, and sub canina 9020 aredisposed on both sides of the face (e.g., suborbital 9015 has amirror-image location on the opposing side of the face, across thenose).

Known tissue properties at any one or more of these locations mayinclude any one or more of soft tissue thickness, modulus data based onforce, deflection, modulus and thickness, soft tissue thickness ratioinformation, and body mass index (BMI).

Second, the skin surfaces on a patient's face significantly deform whena CPAP patient interface is strapped onto a face. Using the initial 3Dmeasurement of the geometric surfaces of the head and face in therelaxed state, the changes in the surfaces may be predicted usingknowledge of the skin/soft tissue properties, discussed above, andsimulation software. Such a technique may be an iterative, optimisationprocess coupled with the design process.

Third, given a patient's sleeping position, the skin surfaces may shiftdue to gravity. Predicting these changes, by utilising knowledge of skinand soft tissue properties along with simulation software, can help todesign more robust comfortable and high performance patient interfacesin various sleeping positions. As shown in FIG. 9C, data relating toupright to supine change in geometry may be collected and used from oneor more areas of interest such as nasian 9003, end of nasal 9004,mid-philtrum 9005, chin-lip fold 9008, suborbital 9015, lateral nostril9017, naso-labial ridge 9018, supra canina 9019, sub canina 9020.

5.11.3.2 Simulating Experienced Pressure 4402

Finite Element Analysis (FEA) software (such as ANSYS) may be used tocalculate an approximate pressure value experienced between the patientinterface contact area and the patient's face. In one form, inputs mayinclude geometry of the face in the ‘Relaxed’ and ‘Deformed’ states,characteristics (e.g. measured elastic moduli, or sub-structures withknown characteristics such as stiffnesses) of the face at variouslocations thereof. Using such inputs, a finite element (FE) model of theface may be constructed, which could then be used to predict one or moreresponses of the face to an input (such as deformation or load). Forexample, the FE model of the face could be used to predict the deformedshape of the face for a given pressure level in the patient interface(e.g. 15 cmH₂O). In some forms, the FE model may further include a modelof the patient interface or a portion thereof, such as a cushion,comprising a geometry of the cushion and its characteristics (e.g.mechanical properties such as elastic modulus). Such a model couldpredict a deformation of the cushion when an internal load is appliedthereto, such as from an application of CPAP pressure, and a resultinginteraction of the cushion with the face, including the loads/pressurestherebetween, and a deformation of the face. Specifically, the change indistance at each point between the relaxed state and the deformed statealong with the corresponding tissue properties may be used to predictthe pressure experienced at a given point (e.g., at a cheekbone).

5.11.3.3 Specific Feature Processing 4403

Certain areas or features on a patient's face may require specialconsideration. Identifying and adjusting for these features may improvethe overall comfort of the patient interface. From the data collectionand estimation techniques discussed above, suitable features may beapplied to a custom patient interface.

Specifically, different areas on a face may have different requirements.The table below illustrates one example of the anticipated areas ofinterest:

Pressure Pressure Shear Shear Area on Face Sensitivity ComplianceSensitivity Compliance Nose Bridge HIGH LOW HIGH MED Sides of Nose HIGHLOW N/A MED Corner of Nose MED MED N/A HIGH (Upper Cheek) Sides of MouthLOW HIGH N/A HIGH Lower Corner LOW/MED MED N/A MED of Nose Bottom LipLOW/MED LOW N/A HIGH Top Lip HIGH LOW/MED N/A MED

In addition to the pressure sensitivity, pressure compliance, shearsensitivity and shear compliance indicators above, specialconsiderations may be accorded to facial hair, hair styles, and extremefacial landmarks, such as a pronounced nose bridge, sunken cheeks or thelike. As used herein, “shear sensitivity” refers to the feeling of shearby the patient, while “shear compliance” refers to how willing thepatient's skin is to move along or compliant with shear.

5.11.3.4 Applying Patient Preferences 4404

In addition to the areas of interest, the synergy between a user and adesigner may provide a more pleasant experience and better patientinterface for the patient's needs. Such patient input may be applied inapplying patient preferences 4404.

In one example, an online portal is created to allow the patient toengage in the design process. To provide the optimum comfort andperformance for custom patient interfaces, creating dialogue between thepatient, the designer and/or manufacturer is advantageous. One option iscreating an environment where the patient can provide inputs to theirpatient interface design and where the designer and/or manufacturer canalso provide recommendations via an online portal.

Within an online portal or smart phone application, patients may createtheir own personal online profile where they can perform a variety oftasks such as keeping track of therapy progress, uploading 3D data, ordesigning a custom patient interface through aesthetic and/or functionalfeatures. In some examples, aesthetic inputs may include choosingcolours, schemes and/or patterns to appear on their patient interfacesystem. User may also upload patterns or colours to their patientinterfaces, choose material finishes (e.g., contact, frame or headgearmaterials) for comfort, tactility or temperature preferences, and/orchoose between varieties of headgear styles. In some examples,functional inputs may include headgear elasticity (e.g., tensilestrength properties), patient interface type (e.g., nasal, full face,etc.), headgear attachment points (e.g., the number of points desired,the trade-off between stability and bulkiness or the type of attachment,such as magnets), patient interface volume (bulkiness vs. breathingcomfort), additional sensors in the patient interface, elbow/swivelchoices, vent location and direction, whether the user wears glasses,type of skin, such as oily or dry skin. Users may also order patientinterfaces or other products, and engage in social networking forums,where patients can share their CPAP experiences or patient interfacedesigns.

FIG. 10A illustrates one example of nose patient interface 10000 thathas been adjusted to accommodate patient input 10010, 10020, 10030. Inresponse to first input 10010 regarding glasses, a corresponding padding10012 is added in the desired location. In response to second input10020 regarding gel addition, a corresponding gel portion 10022 is addedadjacent the nostrils. In response to third input 10030 regarding thebeard, beard patch 10032 is added to increase comfort. Thus, theseadditional patient-specific criteria are considered in designing andmanufacturing the patient interface.

The information may flow in both ways between the patient and thedesigner. That is, in addition to patient input, the designer maysuggest certain features to the patient. For example, the designer mayprovide the range of product options as well as recommendations to thepatient. Such recommendation may be based on queries to the patient,device usage data, such as data relating to leak, hours of usage, ordata from the collected data (e.g., geometric surfaces or pressuremaps), such as skin tone and colours to generate aesthetically pleasingpatient interfaces, patient interface size and type, and/or headgearstructure from the head shape. Elbow/tube type and orientation may alsobe considered and a recommendation relayed to the patient regardingsame.

Thus, the designer and/or manufacturer may recommend different headgearfor patient 10100 and patient 10200 of FIG. 10B based on the differencesin their head shapes to increase stability of the patient interface.Additionally, a specific headgear, which may not be suitable for patient10200 may be indicated as a poor choice due, for example, to anticipateddiscomfort.

The proposed system may also provide a feedback tool by which the personis able see their customised design placed on to a 3D rendering of theirface to create a virtual rehearsal shown in FIG. 10C. Thus, in oneexample a patient's head 10300 is scanned and data is sent to a virtualportal 1400 where it is rendered on a number of patient interfaces10401. The user may choose a specific type of patient interface or atype of headgear, as well as adjust a plurality of parameters such asstyle, colour, etc. After completion, the patient may then print apicture of the design rendered on the face (or the design alone) andsend the chosen design for further processing and/or manufacturing.

5.11.4 Output Data Packages 4450

As used herein “Data Package” refers to the data packet that is used asthe input for the process of designing the patient interface. Within theData Packages are several subsets of data including, the data that hasbeen captured at patient data collection 4300, the enhanced version ofthe data after specific feature processing 4403 and the user inputs4304.

These data packages contain all the input information required for thedesign of the patient interface in patient interface design 4500.Patient interface design 4500 may include algorithms that utilize thedata packages as an input to create a customised patient interfacedesign that responds directly to the information within the datapackage. Alternatively, the data package may be used directly bydesigners to create the custom patient interface design, a high labourbut fully handmade method. The data packages can be stored for futureuse if needed. Two data packages have been briefly discussed. Theseinclude a geometric surface model design package 4451 and a pressure mapdesign package 4452.

5.11.4.1 3D Geometric Surface Model Design Package 4451

A three-dimensional geometric surface model design package 4451 mayconsist of the 3D geometric surface model of the patient's face and headafter the capture data has been processed in data processing 4400.Alongside this 3D model, the package may also contain the patientpreferences and inputs that they have specified.

5.11.4.2 Pressure Map Design Package 4452

Pressure Map Design Package 4452 may include a pressure map of thepatient's face after the capture data has been processed in dataprocessing 4400. Alongside this pressure map, the package may alsocontain the patient preferences and inputs that they have specified.

5.11.5 Patient Interface Design 4500

Patient interface design 4500 may include a system of algorithms thatprocess data packages 4451, 4452. Patient interface design 4500 acts asa smart system that responds to the inputs, which are the data packages,and calculates the output as the designed custom patient interface fromthat particular data package. Thus, patient interface design 4500 willtake the incoming data packages and use the data (either 3D geometricsurfaces and/or 2D pressure map) along with the patient preferenceinputs and calculate at least one custom component.

FIG. 11 is a schematic illustrating the basic elements of patientinterface 11000. The basic patient interface structure 11000 may beseparated in to three main parts, each of which can be eitherstandardised or customised individually, concurrently or in anycombination as required. As shown, patient interface structure 11000includes frame 11001, intermediate structure 11002 and sealing element11003.

Frame 11001 is generally considered the component that provides anoffset distance from the patient's face and an associated functionaldead space; it is also the component to which the pneumatic connectionfrom the flow source is most likely to be made. Intermediate structure11002 has several functions. First, intermediate structure 11002 aids inoffsetting frame 11001 from the face. It also provides an attachmentmethod for frame 11001 and sealing element 11003. It may provide ageometric transition between a standardised frame and custom sealingelement 11003 or vice versa. Intermediate structure 11002 may also becustomised through either geometry or material properties to provideimproved user comfort/efficacy of treatment. Sealing element 11003consists of either a geometry designed into an elastomer to achieve aseal (e.g., a membrane, similar to that of current patient interfacedesigns) or a material of appropriate properties that enable a seal suchas a soft elastomer, foam, gel, textile and/or a sticky/tacky material.

5.11.5.1 Frame Customisation

To increase functionality and comfort, frame 11001 may be customised ina variety of methods. Three such methods will be described withreference to FIGS. 12A-C. It will be understood, however, that thecustomisation is not limited to these three examples and that variationsof each example are possible.

In a first example (FIG. 12A), a patient's face 12050 is scanned usingany of the techniques discussed above in data collection 4300. Analgorithm may then offset and trim surfaces such as, for example,non-sealing surfaces of the patient's face 12050, to produce a patientinterface frame 12010 that is a transformed copy of the patient's face,offset by a predetermined offset value, O1. In some examples, the offsetvalue O1 is between about 0 mm and about 20.0 mm. In at least some otherexamples, the offset value O1 is between about 5.0 mm and about 10.0 mm.The offset value O1 may be variable around the face or constant. Thus,in some examples, a constant offset value O1 of 5.0 mm is applied toeach point of the patient interface. Alternatively, the offset value O1may vary such that an initial offset value O1 of 5.0 mm is appliedadjacent the nose, and a different offset value O1 of 6.0 mm is appliednear the cheekbones. In this example, functional dead-space and ventflow requirements may be controlled (e.g., functional dead-space andvent flow requirements may be reduced or increased). The resultingpatient interface may also be made compact, limiting visualobstructiveness. Contact pressure may be evenly distributed andstability may be increased. Headgear tension may also be reduced in thismanner. The increased contact area may also improve sealing as will bediscussed in greater detail below.

If the offset value O1 is set to 0 mm, frame 12010 of the patientinterface may sit in full contact with the patient's skin. In thiscontact, in order to increase comfort, the patient interface may beunitarily formed from one portion. As such frame 12010 may be made froma soft or elastomeric material, unlike ‘traditional’ frames. In thisexample, the nares or nostrils may act as fixture points.

In a second example (FIG. 12B), a patient's face 12050 is scanned and analgorithm copies and offsets relevant surfaces to create a custom frameassembly 12020 having a shape in the sagittal plane that blends thesesurfaces into a standardised cushion interfacing surface. This techniquemay reduce the functional dead space as well as the vent flowrequirements. The resulting patient interface may also be made compact,limiting visual obstructiveness. This example may also provide a morestandardised lock/key interface between frame 12020 and a correspondingintermediate structure or sealing element 11003 resulting in improvedmanufacturing economy because only certain inserts may need to becustomised as opposed to customising the entire apparatus.

In a third example (FIG. 12C), a patient's face 12050 is scanned and analgorithm copies and offsets relevant surfaces to create a custom frameassembly 12030 having a shape in the coronal plane that blends thesesurfaces into a standardised tube/elbow attachment point. This techniquemay evenly distribute contact pressure, increase stability, reduceheadgear tension and allow for standardisation similar to frame 12020.Thus, frame 12030 may provide a lock/key interface with variouselbows/short tubes, or use an existing array of elbows (e.g., choose oneof three or more elbows). Custom elbows may also be created, if desired.

Existing frames/headgear combinations may also be used without beingcustomised. In these examples, intermediate structures and/or sealingelements 11003 may be customised and coupled to a standardised frame, oran array of standardised frames. In the following examples, one lesscomponent is customised resulting in a decreased price and improvedmanufacturability.

In FIGS. 12D-F, three standardised frames 12040, 12041, 12042 arepresented to users. Based on data collection 4300, an algorithm maydecide which of standardised frames 12040, 12041, 12042 best suits thepatient. Customised intermediate structures and/or sealing elements11003 may then be separately formed and configured to interlock with thestandardised frames. The appropriate frame may be chosen based on facesize and may include keyed interlock systems 12060 for mating with othercustomised components 12070 of a patient interface.

5.11.5.2 Intermediate Structure Customisation

As with the frame, intermediate structure 11002 may also be eitherstandardised or customised. To achieve optimum comfort and seal, theintermediate structure can be customised from the patient data toprovide macro and/or microfit to the patient. As used herein, a microfitis a relatively small adjustment by the sealing surface or material toaccommodate deformations by less than or equal to 2 mm. An example forthe intermediate structure 11002 capable of performing this function isone made of foam or soft durometer silicone. Moreover, a macrofit is arelatively larger adjustment by the sealing surface or other patientinterface components to accommodate deformations greater than 2 mm. Anexample for the intermediate structure 11002 capable of performing thisfunction is higher durometer silicone (or thicker) or foam displacement.Thus, in one example (FIG. 13A), intermediate structure 13010 mayinclude two components adjustable for macrofit and/or microfit. A firstcomponent 13012 may be formed of a rigid or semi-rigid material toprovide the proper macrofit. In some examples, the material of firstcomponent 13012 may include plastics, thermoset or thermoplasticelastomers or any other suitable polymer or combinations thereof. Forfiner adjustments (e.g., a microfit), a second component 13014 may befabricated and coupled to first component 13012 to form a soft andcompliant surface. Materials for second component 13014 may includesilicone, foam, soft thermoplastic elastomers, tacky silicone, fabric orsuitable combinations thereof. When patient 13050 wears a patientinterface having intermediate structure 13010 with two components13012,13014 adjusted for the proper macrofit and microfit, superiorcomfort and sealing are possible.

Customised intermediate structures 13010 may provide optimum sealingaround the patient interface, increased comfort for the patient and aneven distribution of contact pressure. Additionally, materials may beselected for different portions of the intermediate structure asdesired. For example, the nose bridge area may include a softer grade ofsilicone, foam or thermoplastic elastomer than other areas, whichinclude a single grade of silicone or other harder materials. Patientpreferences may also be included in material selection. Thus, materialsmay be selected for relieving pressure points, providing better sealingand increase comfort and/or stability.

Intermediate structure 13010 may also act as a customised component forsecuring together the frame and sealing elements. Additional benefitsinclude the ability to provide a method of smoothly transitioning from acustom frame assembly to standard sealing elements and vice versa,enhance aesthetics, and allow the decoupling of components forreplacement of at least one component. Predetermined lock/geometry mayfurther be used to prevent accidental coupling of the components toimproper components of other devices or competitor products withincompatible functionality.

As seen in FIG. 13B, a given intermediate structure 13010 may becoupleable to more than one size and/or shape of frames 13040, 13042. Inat least some examples, a single intermediate structure may becoupleable to a line of frames in various sizes, shapes and/orvarieties. Thus, intermediate structure 13010 may act as an adapter forcustomised sealing components. With this ability, patient's may retain apatient interface, while improving sealing and/or comfort accordingly.

5.11.5.3 Sealing Element Customisation

The third component that may be customised is the sealing element 13510,which may provide superior sealing and comfort through customisation.One example of such customisation was briefly discussed with referenceto FIG. 11 and the user input. Optimum comfort and seal may be achievedthrough the selection and placement of suitable materials atpredetermined locations. For example, for the nose bridge area, a softergrade of silicone, foam or soft thermoplastic elastomer may be used. Thechoice of materials may also be based on patient preference and mayinclude silicone cushion, foam, fabric, textiles, tacky silicone,thermoplastic elastomers, gel, polyurethanes, and other suitablepolymers, and combinations of any of these materials. With the properchoice of material, relief from pressure points may be realized.Moreover, pressure and shear sensitive areas on the patient's skin(e.g., facial hair, scars, etc.) may also be adequately addressed. Insome examples, the proper material may be flexible to help improve thepatient interface-to-face interaction on a micro level.

The geometry of a sealing element 13510 may be customised to match thecollected patient data for comfort and seal. Such geometricmodifications may influence both the macrofit and the microfit of thedevice. To provide adequate sealing, the three-dimensional geometric andtwo-dimensional pressure data of a patient's face 13550 may determinethe geometric shape of a sealing element 13510 (FIG. 13C). For example,the thickness of the sealing element 13510 may be partially based on thetwo-dimensional pressure map or the deformed three-dimensional surfacedata. By analysing both the relaxed surface date (shown, by way ofexample, in solid lines) and deformed three-dimensional surface data(shown, by way of example, in dashed lines) and the pressure map, animproved sealing element 13510 may be custom-tailored to patient 13550.Thus, sealing element 13510 may be modified to the shape of sealingelement 13511 in view of the deformed three-dimensional surface data orthe pressure map.

Additionally, the sealing surface area (the total area of patientinterface contact on the patient's skin) may be selected from a range of1 cm² to 30 cm² to improve the patient interface seal or distribute thecontact pressure for better comfort. FIG. 13D illustrates two possiblepatient interfaces 13500, 13502 for patient 13550, each having a sealingelement 13520, 13522. Sealing element 13520 may provide a sealing areaof approximately 15 cm², while sealing element 13522 may provide asealing area of approximately 7 cm². For proper sealing of a patientinterface is that there be a continuous line within the region ofcontact where the sealing force in grams per square centimetre exceedsthe air pressure in the patient interface. This condition may be met inmany parts of the region of contact but there must be a contiguous linewhere it is met. By analysing pressure data and both relaxed/deformedstates, a proper sealing area may be selected to provide adequatesealing while reducing unnecessary bulk of the patient interface 3000.

The thickness and material of the sealing element 13510 may contributeto patient interface comfort. In some examples, the thickness of thesealing element 13510 may range from 0 mm-50 mm to match a patient'scomfort preferences. Thus, the optimal sealing element 13510 woulddistribute contact pressure effectively, provide optimal sealing basedon sealing surface area, improve stability of the patient interface 3000with regards to differences in facial structure and/or sleepingpositions and enhance comfort and sealing based on any of the techniquesdiscussed herein.

5.11.5.3.1 Cushion Fillers

In embodiments having cushions, the cushions may include fillers toprovide a patient mask with a comfortable fit and effective seal fortreatment with a respiratory treatment apparatus. In a typicalembodiment (e.g. shown in FIGS. 14A-14B), a mask cushion 14102 mayemploy an inner cushion component 14104. An outer barrier 14106, whichmay optionally be a membrane, may be applied to the inner cushion toform a chamber 14108 or cell with respect to the inner cushion component14104. The chamber may optionally be flexible. The outer barrier 14106and chamber 14108 can serve as a patient contact side of the maskcushion 14102 relative to the inner cushion component. Thus, in someembodiments the inner nature of the cushion component may be more distalwith respect to a mask-to-face point-of-contact with the patient whencompared with the more proximal outer nature of the barrier or barriermembrane that may be at least in partial contact with a facial featureof a patient. Moreover, the inner cushion component may be wholly orpartially encapsulated by the outer barrier. In such a case, the chambermay be a cavity formed by an outer barrier and inner cushion component.Additionally, it will be understood that one or more of the componentsmay be omitted. For example, chamber 14108 and/or outer barrier 14106may be omitted, resulting in an inner cushion component 14104 that is indirect contact with the skin.

Typically, the inner cushion component may be soft and/or elastic andthe outer barrier may be a pliable and/or elastic layer of natural orsynthetic material. However, in some embodiments it may be formed atleast in part with a rigid or semi-rigid material. Optionally, the innercushion component may serve as at least a partial filler of the outerbarrier.

In some embodiments, each barrier or membrane may be formed fromsilicone, polyurethane and/or polyethylene. The barrier may even beformed of a viscoelastic material. A pliable and/or elastic nature ofeither or both of the components and/or membranes of the mask cushionmay serve to provide the chamber with a flexible property. In someembodiments, the barrier may be thin, such as on the order of the rangeof about 0.2 to 5 millimeters. Preferably, the barrier may be about 0.2to 0.6 millimeters. However, in some embodiments it may even exceed thisrange and may also be sufficiently pliable to permit sealing with theparticular areas or contours of the patient's face to permit acomfortable and effective seal while also maintaining the innersubstance of the chamber.

Moreover, the outer barrier can serve to retain a chamber material 14110within the chamber, such as a gas or liquid, between the inner cushioncomponent and the outer barrier or outer barrier membrane or within anarea substantially confined by the barrier. The chamber material mayfill or only partially fill the chamber depending on the desiredresponse characteristics of the mask cushion. Preferably, the chambermaterial may move, flow, permeate within the chamber or otherwise deformin response to applied patient contact pressure on the flexible orelastic components of the cushion such as the outer barrier or outerbarrier membrane. For example, an outer layer of liquid may reside andflow within the chamber formed between the outer barrier and the innercushion component. Thus, in some embodiments, the structure andflexibility provided by the inner cushion component can enable a maskutilizing such a cushion component to conform with a patient's macrofacial features (e.g., nose and/or mouth) while the outer layer of thechamber may accommodate for micro facial topography. Similarly,depending on the chosen viscosity or deformability of the chambermaterial of the chamber, the outer barrier may respond more rapidly thanthe inner cushion with respect to changes in facial contour resultingfrom movement during use (e.g., facial expressions) so as to maintain amore effective seal against respiratory treatment leaks.

As illustrated in the embodiment of FIGS. 14C and 14D, the outer barrier14106 may form a chamber that may surround a perimeter of the innercushion component 14104 (shown as line P) in addition to extending alonga length (shown as line L) of the inner cushion component. However, thechamber and inner cushion may be formed in various configurations. Thechamber may be formed by one or a plurality of discrete cells that eachcontain the same chamber material or different chamber materialsdepending on the desired flexibility to be achieved by the differentsections or cells of the chamber. Additional example embodiments showingvarious chamber configurations are illustrated in the cross-sectionalillustrations of FIGS. 14C through 14E.

In FIG. 14C, a chamber 14108 extends along a partial perimeter of theinner cushion component 14104. In this example, a chamber 14108substantially extends along a limit of an Interior Side Wall portion(shown as “ISW” in FIG. 14C and FIG. 14D) of the mask cushion and alonga limit of a Face Contact top Side portion (shown as “FCS” in FIG. 14Cand FIG. 14D) but not substantially along the Exterior Side Wall portion(shown as “ESW” in FIG. 14C and FIG. 14D). In FIG. 14C, the chamber14108 extends substantially along a limit of the face contact top sideportion of the mask cushion without extending substantially along eitherof the interior side wall portions or the exterior side wall portions.In the example of FIG. 14E, the chamber is formed along a limit of aportion of the facial-contact top side portion of the mask cushion toform a chamber flap F that may be flexible. Although the flap F portionof FIG. 14E is illustrated extending from the facial-contact top sideportion near an exterior side wall portion, an alternative or additionalflap portion (not shown) may optionally extend from the facial-contacttop side portion near the interior side wall portion. Optionally,although each of these embodiments is generally shown as a substantiallycontinuous enclosed chamber, the interior side wall portion, exteriorside wall portion and the facial-contact top side portion in someembodiments may each be formed by a discrete cell of the chamber and maybe adjacent to one or more of the other discrete cells of the chamber.

Beneficially, the different materials or material properties of thecomponents of the cushion may be combined to yield a synergisticperformance when used as a cushion for a respiratory mask. Thus, asillustrated in FIG. 14F, the inner cushion component of any of theembodiments may be a soft springing foam 14560 such as an open cell orclosed cell foam. This component may optionally be formed with apolyether, urethane or other elastomer 14562. It may also be formed witha gel 14566 or such a gel with air bubbles, beads, pellets, polyesterand/or foam balls 14564 therein. In such a case, the beads, pelletsand/or foam balls may be soft and/or flexible. Optionally, such beads,pellets and/or foam balls may be in a liquid or any other of the innercushion component or chamber materials. The inner cushion component mayeven be formed with an open cell foam that is saturated or impregnatedby a gel. By way of further example, the inner cushion component may beformed with three dimensional spacer fabrics such as in a matrixstructure or other three dimensional structure or pattern.

When the chamber material is a flowable substance or other materialhaving a sufficiently low viscosity to promote its movement throughoutthe chamber, one or more benefits discussed herein may be achieved. Forexample, the material may be a gas such as air or a liquid such aswater, a liquid gel, saline solution or oil. The material may also besterile. With such a low viscosity, the chamber material 14110 may notonly move through the chamber, but it may also optionally flow so as topermeate through or within the material or structure of the innercushion component. Thus, in some embodiments, the chamber material maysaturate the inner cushion component or move through a porous or openstructure of the inner cushion component to the extent that the portionof the inner cushion component is encapsulated or retained within theenclosure of the chamber. Such a permeation of the fluid within, forexample, a foam inner cushion component can provide an inner cushionwith a density greater than without the fluid and it can then provide adifferent feeling for a patient upon contact or under pressure.

An example of a migration of the chamber material, such as a fluid orgas, between the chamber and the inner cushion component may beconsidered with reference to FIGS. 141 and 14J. In this example, themask cushion 14102 has the chamber material 14110, represented by “+”symbols in these figures, within the chamber 14108. When an externalforce FC, such as a patient contact on the outer barrier 14106 asillustrated in FIG. 14J, is applied, chamber material 14110 may flow(illustrated by the arrows of FIG. 14J which cross the boundary betweenthe inner cushion 14104 and the chamber 14108) as the mask cushion iscompressed. Thus, under a load, the outer chamber 10 material maymigrate to the inner cushion component, or an aperture thereof, at arate that is viscoelastic in nature. Releasing the load or force FC maythen permit the mask cushion 14102 to return to its non-compressed stateillustrated by FIG. 141. In such a case, the chamber material 14110 mayreturn to the chamber 14108 as the force FC recedes.

However, in some embodiments, such as the cushion illustrated in FIG.14F, an optional internal barrier membrane 14512 may be included toimpede or prevent the chamber material from permeating through or withinthe material or structure of the inner cushion component. In this way,the internal barrier membrane may internally encapsulate the innercushion component and prevent material aggregation between the chamberand the inner cushion component. Thus, inner and outer barrier membranescan serve as a dual seal bladder for the chamber material to separatethe chamber from the inner cushion component. Thus, for example, gels ofdifferent viscosities could be utilized for the inner cushion componentand chamber material. For example, a gel with a higher viscosity may beutilized for the material of the inner cushion component (within theinner barrier membrane) and a lower viscosity gel could be utilized forthe chamber material in the chamber. Similarly, the flow of a fluid suchas water in the chamber can be prevented from combining with, forexample, a gel inner cushion component with the inner barrier membranetherebetween. By way of further example, by preventing a permeation ofthe fluid such as water within, for example, a foam inner cushioncomponent, the inner cushion may be provided with a lighter feel forpatient use. Furthermore, by varying the ratio of a quantity of foam forthe inner cushion component with a quantity of liquid in the chamber,the hardness or comfort of the mask cushion as perceived by the patientmay be adjusted. Similarly, by otherwise varying the degrees of theflexibility or pliability of the inner cushion component with respect tothe flexibility or pliability of the chamber and/or outer barrier canprovide unique mask performance qualities.

As further illustrated in FIG. 14F, the components of the mask cushionof the present technology may include an integrated or separate maskinterconnect component 14516, which may optionally be adhered to anotherportion of the mask cushion with an adhesive 14518 or other fasteningcompound or component. The mask interconnect component can serve as anattachment device to combine the cushion with a mask frame for a maskassembly. In this example, the mask interconnect component 14516includes optional clips 14520 for temporarily affixing the interconnectto the mask frame. The mask interconnect component 14516 can also serveas a cap to assist with retaining the chamber material within the outerbarrier membrane. Thus, the interconnect may be adhered with the outerbarrier membrane. It may also optionally be adhered to the inner cushioncomponent and inner barrier membrane, if implemented in such anembodiment.

A further implementation of a removable mask cushion 14102 for a maskframe 14690 is illustrated in the embodiment of FIGS. 14G-H. In thisversion, the flexible nature of the material used for the cap portion14672 of the inner cushion component 14104, permits the cap portion14672 of the inner cushion component to serve as an interconnect to amask frame. In the example, the mask frame includes a channel 14692sized for fitting with the cap portion. As shown in FIG. 14H, the maskcushion may then be push fit or otherwise inserted into and retained bythe channel 14692. The compression fitting formed by ridges 14694 of thechannel 14692 and the flexibility of the cap portion 14672, outerbarrier membrane and/or inner cushion component create a pressure sealto prevent a treatment gas pressure leak between the mask frame and maskcushion when gas is supplied to the mask via a gas port 14696 of themask frame.

5.11.5.3.2 Bespoke Gel Cushions

The filler composition, such as for insertion within the chamberpreviously described, or one or more compartments of a cushion or abladder of a mask cushion, may itself be selected based on collectedpatient data to optimise comfort and/or performance. Such compositionsmay include the use of one or more gels, or other flowable materials.When disposed in a cushion, the different types of gels or materialsprovide varying structural properties, allowing for customisation foreach patient.

In one example (see FIG. 14K and FIG. 14L), a mask cushion 14102 mayemploy an inner cushion component 14104 and an outer barrier 14106,applied to the inner cushion to form a chamber 14108 or cell withrespect to the inner cushion component 14104. Properties of cushion14102 may be varied by, for example, customising the amount, shape,alignment and/or other property (e.g., thickness, shape, flexibility,directional flexion) of each material added to each compartment of theinner cushion component 14104 and in its configuration. Thus, in theexample shown in FIG. 14K, a first layer 14802, a second layer 14804 anda third layer 18106 are stacked in inner cushion component 14104. Asshown, each of the layers includes a different material. Moreover,though three layers of three materials are shown, any number of layersor materials may be used and variations are possible as will bedescribed in greater detail below. In this example, the three layersinclude three different materials. However, one or more of the layersmay include the same material as another layer. It will be understoodthat in this document, references to different ‘materials’ are not to belimited to materials of varying chemical composition. For example,references to different materials may include use of one substance (e.g.of a single chemical compound of mixture) in different configurations toachieve varying material properties (e.g. for use in variousaforementioned layers). For example, by varying a density of acompressible substance, or by varying a porosity of a foam-likesubstance, variations in material properties may result, effectivelycreating different ‘materials’.

The materials disposed in layers 14802, 14804, 14806 may be flowable,such silicones or gels of varying properties, such as, for example, gelshaving varying durometer or porosity. Having materials with varyingproperties may allow the use of layers of flowable material of varyingshapes and thicknesses to be formed in inner cushion component 14104 toachieve the desired properties for the cushion 14102. In some cases,different types of materials may be used in a single cushion (e.g. acushion may include both a gel and a predetermined grade of silicone).In at least some examples, varying grades of silicone are used for thelayers. Moreover, porous foam-like silicone may be used, in which casethe porosity/density of the foam may be varied to adjust the resultingmechanical property of the substance in the layer, and as a result, thecushion itself. Additionally, “hollow’ layers (e.g., layers of air orother suitable gasses) may be used. Where compressible materials areused, a pressure at which the material is contained (e.g. in the innercushion component 14104) may be varied to vary the resulting property.

In some cases, foam-like silicone may be produced from a chemicalreaction, which may produce gaseous by-products. A manufacturing processfor the patient interface (or the inner cushion component 14104) may beconfigured so that the gaseous by-products may be directed to apredetermined location within the patient interface, or to remain in thechamber wherefrom the gaseous by-product may have originated. At leastsome of the hollow layers may be configured to receive the gaseousby-products to fill and/or pressurize the hollow layers. Additionally,or alternatively, the gaseous by-products may be utilised to pressurizeany chambers containing the foam-like silicone that the gaseousby-products has originated from. In some cases, the patient interface(or the inner cushion component 14104) may be oriented such that apredetermined destination location for the gaseous by-product may beabove the source of the gaseous by-product, such that the gaseous-byproduct may rise to the destination location.

Other suitable materials for placement in the inner cushion component14104 may be configured to sense and respond to an external variable,such as temperature. For example, the inner cushion component 14104 maycomprise a layer configured to change colour according to a temperature(i.e., thermochromic). Such a layer may provide a visual feedbackmechanism for a patient (or a clinician) to determine where the innercushion component 14104 may be in close contact with the face.

Layering of each material may be achieved by sequentially providing thematerials and/or varying the quantity of each material which isintroduced to form each layer. The shape and structure of each layer mayalso be varied through the use of different sized compartments in innercushion component 14104 to inject the material into (see, for example,FIGS. 14A-C), or by varying the orientation of cushion 14102 as thematerial is injected. Each layer may be visibly differentiated fromother layers, e.g. by colouring each layer differently, so that visualconfirmation is provided of the layers used to the designer. This mayalso provide a visual confirmation of customisation of the layers usedin the mask to a user, and allow for improved feedback in obtaining datafor the next iteration of the mask. For example, a patient may simplesay that the “red” component is too rigid, allowing the designer toquickly identify the problem and possible solutions. Additionally, bycolouring the materials or layers, aesthetics may be improved orcustomised as desired by the patient. In some cases, one or more layersmay comprise one or more scenting agents, such as according to thepatient's preference, for identification of layers. Furthermore, one ormore layers may include medications, which may be configured to bereleased, such as for absorption through the skin or into the air pathfor inhalation.

Thus, the number of layers and the materials as well as the shapes andthe relative positions of the layers chosen may be selected with thepatient in mind. Using information from data collection 4300, a firstcushion for patient A may be manufactured with material X injected intoa first compartment and material Y injected into a second compartment(or as a first layer and a second layer respectively, in onecompartment). For a second patient, patient B, data collection may showthat material Y is preferably injected into the first compartment andmaterial Z injected into the second compartment (or as a first layer anda second layer respectively, in one compartment).

It will be understood that the layers or compartments need not be of thesame size or shape. For example, in the cross-section of cushion 14102of FIG. 14K, layer 14802 is larger than layer 14804 and substantiallysimilar in size to layer 14806. However, the shapes of the three layers14802, 14804, 14806 are entirely different. For a different patient, thesame cushion 14102 may be selected and the same materials, but the sizeand shape of the layers may vary as in FIG. 14L. In this example, layer14806 is the smallest and layer 14804 is the largest. Thus, greater orless rigidity may be achieved in varying locations by changing the sizeand shape of the layers or compartments.

One or more compartments may be configured to be customisable at anon-going level. For example, one or more compartments may comprise aport through which flowable substances could be introduced or removed.In particular, it may be advantageous to include ports in communicationwith chambers that are to be placed on a relatively sensitive region ofthe patient's face (e.g. nasal bone or lip superior). Thus, for example,if a patient finds that the patient interface as purchased in ‘standard’configuration is applying too much pressure on the patient's nasal bone,the patient may remove a portion of the flowable material in theappropriate chamber through the port.

FIGS. 14M and 14N show one example of a layered gel cushion 14102. Inthis example, layers have been arranged in the vertical direction, sothat the properties of the cushion may vary in the vertical directionfrom the bottom end 14902 (e.g., proximal to a user's mouth) of cushion14102 to the top end 14904 (e.g., proximal to a bridge of a user's nose)of cushion 14102. Thus, a first layer 14912 formed of, for example, afirst gel is used near bottom end 14902, followed by a second layer14914 of a second gel, a third layer 14916 of a silicone and a fourth“hollow” layer 14918 having air disposed therein.

As briefly discussed, the number of layers used may vary, such thatanything from one layer to any number of layers may be used. If a singlelayer is used, a patient interface may still be customised by varyingthe type of flowable material which is introduced into the housing foreach patient, or the quantity of the flowable material introduced.Relatedly, the stiffness of selected portions of cushion 14102 may alsobe varied at each point or different areas (e.g. via varying wallthicknesses or wall material properties such as elastic moduli) usingthis process as the cushion 14102 may be capable of bellowing out as thematerial is loaded into inner cushion component 14104. Thus, a firstquantity of a material may be loaded within cushion 14102 in a firstarea, while a second quantity of a material (or a second materialaltogether) may be loaded within cushions 14102 in a second area, tovary an amount of bellowing of the cushion which occurs in the secondarea in comparison to the bellowing which occurs in the first area. Forexample, the second area of the cushion may comprise a reduced exteriorwall thickness in comparison to the first area, causing the second areato assume a more bellowed shape. This also allows production ofcustomised cushions using standardised tools. Additionally, it will beunderstood that though cushion 14102 are shown as being symmetric, thisneed not be the case.

In some cases, an inner cushion component 14104 may be configured sothat its rigidity may be varied, such as for customisation. In one form,the inner cushion component 14104 may initially be configured to berelatively flexible, such that the inner cushion component may be placedon the patient to be deformed according to the patient's face, and then‘set’ to a higher rigidity. For example, the inner cushion component14104 may comprise a plurality of chambers not in fluid communicationwith each other (see FIG. 14P), and configured to be relatively flexiblesuch that it would deform when placed on the patient's face. Theplurality of chambers may contain flowable materials which, upon mixturewith each other, would increase rigidity. The plurality of chambers maybe separated at least partially by one or more frangible seals 14922configured to be breakable by the patient, for example by flexure of theinner cushion component 14104, and/or by applying a force to a tab 14924connected to any of the frangible seals 14922. The tab may be in a formof a plate protruding from an exterior surface of the cushion. In oneform, the tab may be connected to the inner cushion component 14104 by aperforation, such that it may be removed therefrom. In such anarrangement, the inner cushion component 14104 may be configured that toapplication of force to remove the tab may also break the frangible seal14922.

Furthermore, the inner cushion component 14104 may be configured suchthat the patient would have sufficient time to initiate a reaction toincrease rigidity of the inner cushion component 14104, and place theinner cushion component on the face prior to occurrence of permanentsetting. In other cases, the inner cushion component 14104 may beconfigured with a short reaction time to setting, such that the reactionto increase rigidity thereof may be initiated while the inner cushion isplaced on the patient's face.

The inner cushion component 14104 may comprise with a re-settablematerial to allow a plurality of conversions between a setconfiguration, and a flexible configuration. In one form, the innercushion component 14104 may comprise a thermoplastic material which,when heated, may be flexible to allow the patient to place it upon theirface. Advantageously, use of a re-settable material may allow thepatient to re-configure a patient interface according to any changes toa shape of the patient's face, or to allow for any mistakes causedduring the setting process (e.g. dropping the inner cushion component14104, or incorrect placement).

In a yet another example, inner cushion component 14104 may comprise amaterial that may be ‘set’ to a higher rigidity in portions. Forexample, the inner cushion component 14104 may comprise a photopolymerliquid, which may set (i.e., cure) when exposed to ultraviolet light. Inthis form, the patient may place the inner cushion component 14104 ontheir face and subject the inner cushion component 14104 to ultravioletlight to cure. Additionally, or alternatively, the patient may onlysubject portions of the inner cushion component 14104 to ultravioletlight where curing is desired. In some examples, a laser may be used asa source of ultraviolet light in order to accurately and precisely curethe desired regions, while allowing the other regions to remainflowable.

In addition to varying the number of layers and the number or quantityof materials used in each layer, cushion 14102 itself may be modified inseveral ways to improve customisation. For example, cushions 14102 maybe formed of multiple standard sizes (e.g., small, medium, large,extra-large) or may include inner cushion components 14104 of differingsizes. Additionally, cushion 14102 may itself be formed of materials orin configurations to vary the stiffness and/or be sizes to accept acertain amount of material within a particular region of inner cushioncomponent 14104. Thus, cushion 14102 may range from being substantiallyrigid when no material is disposed therein to being a thin membrane,substantially having no structural rigidity in at least some directions,serving instead as a vessel for accepting a material therein, such as agel, which then provides rigidity. Additional structural elements mayalso be added to the cushion 14102 to stiffen the structure atpredetermined locations. For example, as seen in FIG. 14O, ribs 14112are added across chamber 14108 to increase stiffness at four locations.Ribs 14112 may be formed of thin bands of wire, or co-molded plastic orpolymeric material. It will be understood that the inclusions, location,quantity and/or orientation of ribs 14112 may be varied based on datacollection 4300 to stiffen the structure as desired.

Thus, information from data collection 4300 may be used to produce abespoke cushion. This information may include laser scanning data,passive stereo photogrammetry data, contact collection data, deformingdevice data, pressure mapping data, as well as any other type of datadiscussed above including information related to topography, facialstructural data (e.g. stiffness in various directions), and/orunderlying facial structure (e.g. skin, muscular, and/or bone thicknessto predict and/or derive stiffness data).

Such information from data collection 4300 may be used to form a bespokecushion. In one example, a system may be configured to receiveanthropometric data or other information from data collection 4300 andto select an appropriate cushion or cushion component (such as achamber). The system may then instruct an injector to introduce one ormore materials in at least one layer to the chambers of a cushion basedon the received anthropometric data.

Feedback from the patient may also be used to improve the fit of cushion14102. For examples, images of the patient's face may be obtainedshortly after use of a cushion 14102. The image may indicate areas wherethe pressure between the patient interface and the patient may be toohigh (e.g., by looking for redness that indicates high pressure). Thepatient may also provide feedback regarding areas where there may beleak (i.e., insufficient contact with the skin). Such feedback may besent to the manufacturer or designer via the internet or a smart phoneapplication. Using this data, cushion 14102 may be refined to includeincreased stiffness in leaking regions and/or reduced stiffness whereexcessive pressure was present between the patient and the patientinterface.

5.11.5.4 Volume Scaling

Having considered contact comfort, sealing and stability, attention willnow be turned to physical dead space and breathing comfort. Physicaldead space and breathing comfort correspond to patient interface volume.Thus, having produced the overall shape of the patient interface and thecomponents, a scaling step may be performed to change the volume of thepatient interface in a range from about 1% to about 50%. This scalingmay be either upward or downward. That is, in some examples, a preferredvolume is first determined and the patient interface shape is eitherscaled up or down as desired to control the physical dead-space to matchthe preferred volume. Such scaling may account for comfort and sealingsuch that significant points are unaltered during the scaling process.For example, the contact area may remain the same while the patientinterface is offset outwardly from the patient's nose and/or mouth asdesired. It will be appreciated that scaling the patient interfacevolume may also aid in tuning the vent flow requirements.

5.11.5.5 Headgear and Anchoring Components

In addition to the three elements of the patient interface discussedabove, the headgear may also be customised for patients. Proper headgearperformance may affect a variety of properties including sealing,comfort and aesthetics and may be realized by modifying the componentsand locations of the components.

FIGS. 15A-B illustrate one example of the headgear associated with apatient's patient interface. Patient 15050 is wearing a patientinterface 15002 secured by headgear 15004. In this example, headgear15004 includes first straps 15010 and second straps 15012 attached atfirst ends to patient interface 15002. Second straps 15012 may includerigidizers capable of forming a predetermined shape. First straps 15010and second straps 15012 extend toward the back of the patient's head(see FIG. 15B) and attach to third strap 1514 at neck attachment 15040and crown attachment 15042, respectively. As best shown in FIG. 15B, thevectors formed by first straps 15010 and second straps 15012 arelabelled V15010 and V15012, respectively.

Headgear 15004 may be modified in several ways. First, strap vectorsV15010 and V15012 may be adjusted. By analyzing collected patient datasuch as the clearance of ears, mouth and eyes, as well as the headshape, neck shape and facial contours, the vectors may be modified. Insome examples, depending on the number of attachment points and theclearing of sensitive features on the face (eyes, ears, etc.), vectorsV15010 and V15012 may be adjusted from about 0 degrees to about 90degrees from horizontal plane x.

Second, rigidizers of second straps 15012 may also be modified. In someexamples, by knowing the location of the eyes and the cheek contours,straps 15012 may be formed to follow the contours of the patient's faceand also clear the patient's eyes reducing irritation and viewobstruction from the patient interface.

Third, the lengths of any of straps 15010, 15012, 15014 may be modifiedin view of the collected head and/or neck shape and/or size. Forexample, knowing the circumference of the head at different latitudes(for example, C1), the lengths of the straps may be predicted andrecommended to patients. In some examples straps 15010, 15012, 15014 maybe elastic. In such cases, the length and/or stiffness of the elasticmaterial may be adjusted based on the collected data.

Finally, neck attachment 15040 and crown attachment 15042 may beadjusted in view of collected data on head and/or neck shape and size.In such examples, the geometries of the head and neck shape may dictatethe location (latitude) of the neck attachment 15040 and crownattachment 15042. The length of third strap 15014 may also be adjustedbased on neck attachment 15040 and crown attachment 15042.

Moreover, to improve stability of the patient interface when worn by apatient, anchoring points may be chosen based on the collected data.Like glasses, where the anchoring points are the nose bridge; the nosebridge, mouth, ears and teeth may act as anchoring points for arespiratory patient interface. Thus, by knowing the location of thesefeatures, the patient interface may be designed to perform with greaterstability. FIG. 16A illustrates examples of the anchoring pointsassociated with a patient's patient interface. Collected data may beanalysed using algorithms to decide the optimal locations of theanchoring points. Certain potential anchor points have been identifiedin FIG. 16A and include nose bridge anchor point 16002, mouth anchorpoints 16004, 16006 and ear anchor points 16008. Collecting data andanalyzing the locations of the anchor points from the collected data maybe used to form patient interfaces and headgears with optimalperformance and stability.

Turning now to FIG. 16B, during CPAP therapy the transfer of undesiredmovement from the positioning and stabilising structure 16070 (e.g.headgear) or from the patient 16050 may be decoupled or separated frompatient interface 16060, and specifically from sealing element 16062 viacomponents of the positioning and stabilising structure 16070 or thepatient interface itself that prevent this transfer of seal disruptingforce. This can be achieved by elastic or compliant joint features 16080within a connection between the positioning and stabilising structure16070 and patient interface frame or sealing element 16062. Since thepatient interface is customised, sealing element 16062 be can sensitiveto small physical disturbances so the positioning and stabilisingstructure 16070 and also the patient interface and sealing element 16062can be decoupled from each other to reduce the impact of suchdisturbances. A customised patient interface enables a less bulkypatient interface which may not have sealing element 16062 of atraditional thickness to handle seal disruption forces. A sleekcustomised patient interface with a thinner sealing element 16062 mayobtain stability by maintaining a very reliable static seal throughdecoupling of the seal disruption forces caused for example by tubetorque or patient head movement.

5.11.6 Techniques for Dynamic Stabilisation

In addition to the techniques and examples disclosed above for providingcustomisation of different portions of a patient interface 16110,techniques for dynamic stabilisation may also be employed. As previouslydiscussed, a patient's facial features and skin are not static elements,but deform and move frequently during therapy. Accordingly, techniquesmay be directed to stabilising and providing adequate sealing for thepatient interface 16110 during movement and/or deformation of thepatient's skin and/or facial features. To aid in illustrating thesetechniques, FIGS. 16C and 16D illustrate certain effects of patient headmovement on the patient interface 16110 in different sleeping positions.

As shown in FIG. 16C, a schematic representation of the patient's head16100 is shown lying sideways on a bed pillow 16120. Head 16100 includesskull 16102, skin 16104 and nose 16106, head 16100 further being donnedwith patient interface 16110. When the patient's head 16100 is restingon its side on bed pillow 16120 as shown in FIG. 16C, skull 16102, skin16104 and patient interface 16110 are all generally aligned with axis“Y1” and patient interface 16110 aligns with and is cantered about nose16106 so that there exists adequate sealing between the patient's skin16104 and patient interface 16110 around the nasal region.

Turning to FIG. 16D, if patient 16100 begins to move his head,difficulties in alignment begin to emerge. Specifically, as seen in FIG.16D, when skull 16102 is turned toward bed pillow 16120, patientinterface 161100 does not move as much as skin 16104 and skull 16102 dueto friction between the patient interface's associated headgear 16108and the pillow. Thus, axis “Y2” generally represents skin alignment andaxis “Y3” represents patient interface alignment, Y2 and Y3 beingdifferent from one another. In at least some examples, the differencebetween Y2 and Y3 may be between approximately 1 degree andapproximately 60 degrees or in the range of about 10 degrees and about75 degrees. A patient interface may be configured to compensate for thismisalignment.

Skin movement and/or deformation may be characterised as sheering anddeflection properties in relation to certain facial features. Featuresof a patient interface may be configured to compensate for such movementand or deformation at certain locations on the skin. For example, theskin sheer may occur at suborbital 16205 (shown in FIG. 16E). A patientinterface may be formed to compensate for skin sheer, for example, ofbetween approximately 1 mm and approximately 50 mm, and preferablyapproximately 40 mm of longitudinal movement (e.g., up and down), andbetween approximately 1 mm and approximately 50 mm, and preferablyapproximately 28 mm of lateral movement (e.g., sideways). In otherwords, movement may occur in any direction within a range ofapproximately 50 mm.

A patient interface 16110 may also be manufactured that is capable ofcompensating for up twitch/nose twitch, such as when a patient drawstheir upper lip upwards. Specifically, a patient interface 16110 may beconfigured to compensate for variation of the alar angle 16210 duringtherapy of between approximately 1 degree and 30 degrees, and preferablyapproximately 27 degrees that may occur when the corners of the nose16215 moves upwards due to nose twitching and sideways due to side nosetwitches. This compensation is used to design and configure the shapeand profile of the sealing element 16062 and/or frame 12020. Tolerancesfor the sealing element 16062 and/or frame 12020 are introduced based onthis compensation. For example, if there is less patient movement fromtheir nose twitches, a more precise sealing element 16062 and/or frame12020 may be provided. On the other hand, if the patient's nose twitchesmovements are of a greater distance, more tolerance may be provided forthe sealing element 16062 and/or frame 12020 to minimise or avoid sealdisruption. A patient interface 16110 may additionally or alternativelycompensate for an upward movement of the nose corners 16215 and nosemiddle 16220 which may rise by up to 9 mm and 4 mm, respectively. Thepatient interface may further compensate for an increase in the width16225 of the nose by between about 1 mm and about 4 mm. A patientinterface may also be configured to accommodate a cheek bulge from afirst condition 16300 to a second condition 16305 which may result fromall types of nose twitch motion (e.g., sideways and/or up and down), thefirst condition 16300 and second condition 16305 being spaced by betweenapproximately 1 mm and 10 mm.

FIG. 16G is a top view illustrating the effects of applying a force toheadgear 16352, also referred to herein as a positioning and stabilisingstructure, worn by patient 16350. As shown, a first diagonal force T1 isapplied to headgear 16352 at a location 16A near the patient's ear.Force T1 results in a second force T2 at location 16B at the junctionbetween headgear 16352 and frame 16354 as well as a third force T3 atlocation 16C. In some configurations, a patient interface may beconfigured to outwardly billow at location 16C to isolate the frame frommoving, and decouple the nare frame from movement caused by tube drag,and maintain a seal. In at least some examples, headgear 16352 isconfigured to compensate for a force of between approximately 1 Newtonsand approximately 10 Newtons without diminishing the sealing contact ordisrupting the seal with the patient or causing discomfort to thepatient that are likely to cause red marks on the patient's face.Several examples are shown below for compensating for such a force,although it will be understood that these are mere exemplary and thatother methods and techniques are also possible.

In a second embodiment shown in FIG. 16H, patient interface 16400includes conduit 16401 connected to sealing element 16402, which in turnis attached to a headgear 16403 having a first portion 16404 and asecond portion 16406. As shown, first portion 16404 and second portion16406 may be formed of different materials. Specifically, first portion16404 and second portion 16406 may be formed of materials have differentmaterial properties. For example, first portion 16404 disposed aroundthe back of the patient's head may be formed of a substantiallynon-elastic material (e.g., less elastic than second portion 16406),while second portion 16406 disposed over the cheeks and extending tosealing element 16402 may be formed of an elastic material, that is moreelastic than the first portion 16404. Alternatively, first portion 16404may be formed of a sticky or adhering material that does not easilyslide on or against the patient's skin while second portion 16406 may beformed of a different material that slides over the skin more easily.First portion 16404 and second portion 16406 may be formed of materialshaving different coefficients of friction relative to the skin (e.g.,first portion 16404 having a higher coefficient of friction than secondportion 16406), such that second portion 16406 slides more than firstportion 16404 when similar forces are applied to both portions 16404,16406.

The first portion 16404 may be made from relatively non-stretchablematerial and the second portion 16406 is made from a stretchablematerial. A textile cover or wrap may be provided on the second portion16406. The face contacting surface of the second portion 16406 may beprovided with features (e.g. silicone tabs) or made from a material thatincreases friction to prevent/minimise relative movement between thesecond portion 16406 and the patient's skin. The outer facing surface ofthe second portion 16406 may be smooth to prevent translation of forcesfrom patient movement against a bed pillow or bed linen to the patientinterface 16400. With patient interface 16400, sealing element isdecoupled from most perturbations acting on the headgear as theproperties of second portion 16406 allow it to compensate for stretchingforces and movement. Moreover, forces at first portion 16404 are notfully transferred to sealing element 16402 via second portion 16406.Thus, the headgear 16403 of patient interface 16400 provides a stableand firm hold on the patient's head, and is easy to don and doff.

In a third embodiment shown in FIG. 161, patient interface 16410includes conduit 16411 connected to sealing element 16412, which in turnis attached to a headgear 16413 having a first portion 16414 (e.g.,crown strap) and a second portion 16416 (e.g., side straps). The secondportion 16416 has an elastic inner layer 16417 a that contacts thepatient's skin and has more elasticity than the first portion 16414. Thefirst portion 16414 may be relatively inelastic and unable to stretch,for example, made of a neoprene material. As shown, first portion 16414and second portion 16416 may be formed, second portion 16416 having adouble layer configuration of layers 16417 a,16417 b. The inner layer16417 a (e.g., patient contacting layer) of the second portion 16406 isa material that is rigid in tension and relatively collapsible incompression, for example, a ribbon. The side strap 16416 is lengthadjustable via a buckle 16419. Reducing the length of side strap 16416increases the tension of the elasticity of side strap 16416. At restunder no tension of the side strap 16416, but there is a length mismatchbetween the elastic inner layer 16417 a and outer layer 16417 b of theside strap 16416 and the elastic inner layer 16417 a is slightlybuckled. When tension is applied, for example, by tube torque, the sidestrap 16416 directly translates the tension to the crown strap 16414.Since the operative portions of the headgear 16413 are relativelyinelastic under this condition, there is no stretching of the headgear16413 which may cause seal disruption. With patient interface 16410,sealing element 16412 is decoupled from almost all but extreme forcesacting on the headgear 16413 as the layers of second portion 16416 allowit to compensate for stretching forces and movement. Additionally, theheadgear of patient interface 16410 includes first and second portions16414, 16416 that collapse when compressive forces are applied so thatthe elastic material maintains tension.

In a fourth embodiment shown in FIG. 16J, patient interface 16420includes conduit 16421 connected to sealing element 16422, which is turnis attached to a headgear 16423 having a first portion 16424, a secondportion 16426 and a wireform 16428 extending through second portion16426 and coupling first portion 16424 to sealing element 16422. Secondportion 16426, which may be in the form of a cheek pillow is configuredto traverse along (e.g., slides back and forth) wireform 16428 such asby gliding (e.g., a headgear slide) so that facial friction againstsecond portion 16426 does not translate to movement of sealing element16422. In one example, the second portion 16426 is slidable between thepatient's ear and the patient's upper lip. In other words, the secondportion 16426 can slide between the distal ends of the wireform 16428.As shown, wireform 16428 includes an upper wire and a lower wire,although it will be understood that wireform 16428 may include only asingle wire or more than two wires or other suitable materials orstructures connecting first portion 16424 and sealing element 16422. Asshown, first portion 16424 is formed of silicone or Breath-O-Prene andsecond portion 16426 may be formed from a textile material that may beknitted or woven. With patient interface 16420, sealing element 16422 isfirmly held in place with adequate sealing at the patient's nose even inthe presence of movement or external forces being applied to secondportion 16426. For example, friction between a bed pillow and secondportion 16426 may cause movement of the second portion without acomparable force being applied to the sealing element 16422. Forexample, the maximum amount of force that can be tolerated before thesealing element is disrupted is 10 Newtons. The face contacting surfaceof the second portion 16246 may be provided with features (e.g. siliconetabs) or made from a material that increases friction toprevent/minimise relative movement between the second portion 16246 andthe patient's skin. The outer facing surface of the second portion 16246may be smooth to prevent translation of forces from patient movementagainst a bed pillow or bed linen from to the patient interface 16420.

It will be understood that in some examples, combinations of theembodiments described above are possible. For example, a cheek pillowmay be combined with other portions having different materials orrigidity to further minimize movement of a patient interface 16400.

5.11.7 Custom Nare Covers

While the preceding embodiments have attempted to provide additionalstructures for compensating for forces on the headgear, examples aredescribed below that stabilise the patient interface while minimisingthe size of the patient interface, in one example, particularly the sizeof the sealing element and surface area of the sealing element incontact with the patient's face. In another example, the thickness ofthe sealing element and depth of the patient interface are minimised.FIG. 17A illustrates one such example of a patient interface aimed atproviding both stability and minimisation. In this example, the patientinterface includes a frame assembly in the form of a nare cover 17000that is attached to an air delivery conduit or tube 17005 and headgear17010. Details of each of these components will be separately describedin more detail with reference to forthcoming figures.

FIG. 17B is an annotated diagram showing the structure of the bottom ofthe nose including the position of the nares, subnasale, pronasale,columella, upper vermillion, lip inferior and naso-labial sulcus. A narecover 17000 may be configured to form a seal around a perimeterindicated by dashed line P1 extending along the pronasale, the outerperimeters of both nares and the subnasale, essentially enclosing orsurrounding both nares therein. The perimeter may be minimised by takingcare to not encroach on the upper vermillion, the naso-labial sulcus orthe lips.

The size and shape of each component of nare cover 17000 may becustomised for each patient to provide proper fitment. By obtainingmeasurements as described in data collection 4300, a three-dimensionalmodel of the desired nare cover may be computer generated in part, or inits entirety, for each patient. For example, as shown in FIG. 17C, inthe image capture step, a plurality of markers 17100 are selected on apatient's nose and patient's upper lip (in this case sixteen points ofinterest), and a model of a nare cover 17000 is designed based on thesemarkers 17100. In other examples, markers 17100 may be selected atdifferent locations on the patient's face including the eyes, ears,forehead, chin, cheeks, etc. Markers 17100 may be placed at more or lesslocations, but ideally include placement around the perimeter of eachnare, the columella (i.e., the middle segment between the nares), thenostril sill, the corners of the nose, the alarfacial groove, and theunder profile of the nose. In at least some examples, the number ofpoints varies based on the requisite resolution (e.g., the distancebetween adjacent markers). In at least some examples, the resolutionaround the nose is between about 0.1 mm and about 0.75 mm. Theresolution around the nose may also be about 0.5 mm and may be greaterthan resolution at other areas of the face, which may be only 0.75 mm.The selected markers 17100 may be selected so as to define a plane thatis parallel with the nasolabial angle. A contoured surface, shown asshaded surface 17102, may then be defined by markers 17100 thatcorrespond to the surface of the nose around the nares and a portion ofthe upper lip, the contoured surface having a perimeter that correspondsto perimeter P1 of FIG. 17B.

As previously described with reference to FIG. 17A, a delivery conduit17005 will be connected to the custom nare cover 17000 so that air orother gases can flow therethrough. Movement of delivery conduit 17005may affect the stability of nare cover 17000. Thus, nare cover 17000 maybe configured to receive tube 17005 at a predetermined position, angleand orientation to reduce the effects of hypothetical or expected forcesfrom the tube 17005 onto the nare cover 17000. In one example, duringthe data collection stage, an elliptical position 17120 may be definedin free space below surface 17102, elliptical position 17120 defining aplane pz2 that is parallel to the plane pz1 of the nasolabial angle(FIG. 17D). To minimize tube torque and the resulting expected forces ona custom nare cover, the angle, position and orientation of a tube maybe chosen to reduce the moment arm at the tube-nare cover junction(e.g., a tube connection/connection port of the nare cover 17000) bybringing the junction as close as possible to the patient's face alongaxis Z1 without making physical contact with the patient's face andallowing a sufficient volume for dead space in the plenum chamber offrame assembly 17200. This minimises seal disruption during therapycaused by tube torque and reduces the bulk of the mask by reducing itsdepth.

In some examples, nare cover 17000 may be attached to the patient viaadditional headgear 17010 as shown in FIG. 17A. As shown in FIG. 17E, inorder to manufacture a nare cover with the proper fitment, headgearvectors 17130 for a rigidizer arm 17250 of a headgear may also bedefined. A headgear vector 17130 is an imaginary line that maypreferably intersect the mid-point between the patient's eyes and earsand a point on the nare cover 17000. A slot 17135 or recess or socket isthen defined in the nare cover 17000. The angle, orientation andlocation of slots 17135 are discussed in greater detail below. With theimage capture and modelling completed, components of nare cover 17000may be manufactured and assembled. It will be understood that eachcomponent may be customised for a specific patient. Customisation mayinclude producing a plurality of fitments (e.g., twenty fitments) foreach component, and the patient matched to one of the fitments.Alternatively, customisation may include forming a bespoke componentthat is individually manufactured for a given patient.

5.11.7.1 Custom Frame Defining a Plenum Chamber

As seen in FIG. 17F-I, the customised nare cover 17000 forms part of thesurface of a frame assembly 17200 defining a plenum chamber. Frame 17200may be formed of a rigid, or semi-flexible material and may define agenerally hemispherical or dome-shaped structure. As seen from theinside of the frame 17200 (FIG. 17F), the frame may include an innerwall 17210, and seal receiving surface 17220. Frame 17200 may define aplenum chamber, dead space or cavity between its inner walls 17210 andthe patient's skin, while seal receiving surface 17220 may provide aninterface for accepting a sealing element as will be described withreference to FIGS. 17K-N.

Frame 17200 imparts a 3D shape to the sealing element to form anair-tight housing around both nares and define a small cavity defined bythe perimeter of the two nares and a small distance dl away from thenares (see FIG. 17G-1). Distance dl is typically less than 30 mm, andideally as small as possible without making physical contact with thepatient's face and allowing a sufficient volume for dead space in frame17200. In some examples, the dead space or cavity defined as the areaenclosed within frame 17200 and the patient's skin is defined by anestimation of the space within a truncated cone (FIG. 17G-2) thatapproximates a plenum chamber within frame 17200. Thus, the volumewithin a plenum chamber may be estimated as follow:

Volume=(EH)*Π/12[(ED1*ED2)+(ED3*ED4)+(ED1*ED2*ED3*ED4)^(1/2)]

Where ED1 and ED2 are the estimated diameters of the tube entrance, ED3and ED4 are approximate diameters of the perimeter of the nose markings,EH is the estimated distance of the tube entrance to the nose. In atleast some examples, the size of frame 17200 is a function of theperson's nose size, approximately a multiplier between 1 to 2 times ofthe patient's nose. The height of the truncated cone (i.e. the depth,distance d1, of frame 17200) is controllable and adjustable. In oneexample, distance dl is selected to minimise the dead space in the frame17200 to the lowest distance possible. In another example, the patient'sventing preference may be considered, and distance dl is selected toachieve a user-defined level of breathing comfort and therefore may notbe the lowest distance possible.

5.11.7.2 Custom Vent

As previously noted, frame 17200 may include a plurality of slots 17135,in this example two slots, for accepting headgear. Located between slots17135 is a generally oval or circular aperture 17230 for accepting adelivery conduit (not shown). Frame 17200 may also include vent holes17240 on its outer surface above aperture 17230. The location of thevent holes 17240 on frame 17200 may be such that they facilitate bettercarbon dioxide washout, and to improve breathing comfort. For example,vent holes 17240 may be located adjacent the location of the columellaonly as shown. Although vent holes 17240 are shown on the frame 17200,it will be understood that vent holes may also be located in an elbowlocated on an elbow disposed between aperture 17230 of the frame 17200and delivery conduit 17005. The elbow may be a quick release elbow suchthat the elbow together with the delivery conduit 17005 may bedisengaged by the patient from frame 17200.

The number of vent holes 17240 may be selected based on the dead spacedefined by the plenum chamber (e.g., the volume enclosed within theframe 17200 and the patient's face). The dead space may be calculatedand the number of vent holes required to facilitate better carbondioxide washout, and to improve breathing comfort may be selected. Insome examples, a computer algorithm or a look-up table may be used todetermine the number of vent holes 17240. The number of vent holes17240, the location of the vent holes 17240 on a complex surface of theframe 17200, the geometry/profile of the vent holes 17240 andinlet/outlet direction of the vent holes 17240 is selected based on theintended therapy pressure, intended noise level, intended CO2 washoutand intended diffusivity. These features of the vent may also beselected based on a function of the volume of the dead space. Thesefeatures of the vent may also be selected based on a desired humiditylevel, for example, to prevent rainout. In another example, a baffle ora diffuser may be customised and provided to achieve intended noiselevel and intended diffusivity. Customisation of the vent 17240 mayinvolve automated computational fluid dynamics (CFD) for each patientand/or comparison with lookup tables based on the volume and geometry ofthe volume of the dead space when it has been calculated.

FIG. 17J illustrates frame 17200 after coupling delivery conduit 17005to aperture 17230 and headgear 17010 to slots 17135 via rigidizer arm17250. In one example, rigidizer arm 17250 may be substantially L-shapedand may include a first end 17252 generally extending in the coronalplane for insertion and coupling to slot 17135 and second end 17254generally extending in the sagittal plane for coupling to headgear 17010(e.g., for coupling to any of the straps described above). Rigidizer arm17250 may be substantially rigid and stiff and may be formed of a metalor other rigid polymer such as polypropylene, Hytrel, etc. Additionally,the L-shape of rigidizer arm 17250 may provide stable fixation andsealing of the frame against the patient's skin, receiving headgearforces, for example force F1, and producing a force F2 on the frame17200 to push the frame toward the patient's nostrils. Additionalcustomisation of headgear 17010 will be discussed in greater detailbelow.

5.11.7.3 Custom Sealing Element

In order to provide comfort and superior sealing, a nare cover mayinclude a customised sealing element 17300 coupled to the seal receivingsurface 17220 of frame 17200. The sealing element 17300 may be in theform of a cushion that is attachable to the frame 17200, and may have anadhering or tacky member to preserve a seal against the patient's skinduring patient movement or in the presence of an external force (e.g.,the force of a bed pillow against a portion of the headgear). Such asealing element 17300 may compensate for the minimisation of the frame17200 and may provide a patient-friendly solution to movement, resultingin a more comfortable and less bulky patient interface.

Sealing element 17300 may be configured to fasten onto a portion of thepatient's nose via an adhesive. As shown in FIG. 17K, sealing element17300 may be in the form of a cushion comprising multiple layers. Theexposed layers may be an adhesive layer. Between the adhesive layers maybe a low density (more compliant) foam layer and a high density (lesscompliant) foam layer. These layers are sandwiched together. The foamlayers may together form a thin foam layer 17302. Suitable foams aredisclosed in PCT publication no. WO 2014/117227, incorporated herein byreference in its entirety. In use, the low density foam layer is closerto the patient's face than the high density foam layer. The low densityfoam layer may have a thickness of 4 mm, and the high density foam layermay have a thickness of 3 mm. In other examples, the high density foamlayer may be closer to the patient's face in use. In further examples,there may be a single layer of foam with consistent density. One of theadhesive layers is a pressure-sensitive adhesive (PSA) backing 17304laminated onto or applied to the foam layer 17302. As used herein, theterms sealing element, and cushion may be used interchangeable, althoughit will be understood that the materials described for the sealingelement 17300 are merely exemplary and that other suitable materials maybe used. Other suitable adhesives and/or tacky materials may includesilicone adhesives, acrylic adhesives and adhesives disclosed in U.S.Pat. No. 8,291,906 incorporated herein by reference in its entirety. Theadhesive may be laminated onto a foam material. A silicone-basedadhesive may offer some compliance compared to an acrylic basedadhesive. The silicone based adhesive is re-usable and washed to recoveradhesion, compared to acrylic based adhesives which are generally usedonce or twice. In some examples, foam layer 17302 may include stickyfoam. Sealing element 17300 may be capable of comfortably sticking tothe patient skin on one side, and being coupleable to frame 17200 on asecond side. For example, adhesive may be disposed on both thepatient-contact side and the non-patient contacting side of sealingelement 17300 such that the sealing element keeps the frame 17200coupled to the patient's skin. Alternatively, sealing element 17300 maybe mechanically and releasably engageable to frame 17200 and includeonly one adhesive side for coupling to the patient's skin. In otherexamples, the sealing element 17300 may engage with frame 17200 via ahook and loop fastener. In some examples, sealing element 17300 has aperimeter that corresponds to perimeter P1 of FIG. 17B and may becustomised to form a desired shape based on data acquired in datacollection 4300. The same data collected for forming frame 17200 mayalso be used to form a sealing element 17300 having superior fit for thepatient.

During manufacturing, a three-dimensional model 17310 of sealing element17300 is computer generated for a specific patient may be converted to atwo-dimensional flat profile 17300 (FIG. 17L). The three-dimensionalmodel 17310 of the sealing element 17300 is unfolded and flattened by asoftware program to obtain a two-dimensional flat profile of the sealingelement 17300. The sealing element 17300 may be laser cut from a flatsheet, bagged and labelled with a patient's name, thereby creating acustom sealing element 17300 for each patient and a bespoke or customfit. The conversion of a three-dimensional model 17310 to atwo-dimensional flat profile results in quicker manufacturing,optimisation of storage and easier shipment of the sealing element tothe patient.

In some examples, sealing elements 17300 of several patients havingsimilar dimensions may be grouped to provide a best fit that moreclosely fits the patient's anthropometric features compared toconventional mask cushions which generally are only offered in 1 to 3standard sizes corresponding to the patient's nose width. The groupingmay, for example, include twenty sizes of sealing elements 17300 havinggiven lengths, widths, thicknesses and curvatures with a built-intolerance for each dimension. For each grouping a single flat profile17310 may be manufactured, the single profile being suitable for severalpatients of a given group within a given tolerance. For example, thetolerance for a single profile may be +/−2.5 mm for a length dimensionand +/−2.5 mm for a width dimension.

Sealing element 17300 may be coupled to frame 17200 as shown in FIGS.17M and 17N. Specifically, a first surface 17350 of sealing element17300 may be adhered or coupled to seal receiving surface 17220 of frame17200, while a second surface 17355 may adhere or otherwise provide aseal against the patient's skin. Sealing element 17300 may alsodecoupled from seal receiving surface 17220 as desired. For example, ifthe adhesive on second surface 17355 of sealing element 17300 begins towear away, reaches its end of life, or if sealing element 17300 needs tobe replaced, it may simply be discarded and another sealing element17300 may be installed in its place. In at least some examples, sealingelement 17300 includes a dual-layered foam construction having anadhesive. The first layer of foam may be disposed on the surfaceproximal to the frame during use and may be stiffer than the secondlayer of foam, which is to be disposed proximal to the user's faceduring use. Such a dual-layer construction may allow for macro and microadjustments, and ensures a reliable and comfortable seal for thepatient. As previously noted, adhesive may be provided on both sides ofsealing element 17300. In some examples, the adhesive on the first layerof foam (e.g., the layer adjacent the frame 17200) has more adhesivestrength than the adhesive on the second layer of foam (e.g., the layeradjacent the patient's skin). Such a configuration may allow the patientto adjust the position of the frame 17200 without the sealing element17300 becoming detached from frame 17200. It will be understood that theuse of adhesive is merely optional and that other methods of couplingthe sealing element 17300 to frame 17200 are contemplated such asmechanical engagement or magnetic engagement.

5.11.7.4 Custom Headgear

The headgear 17010 of the patient interface may also be customised.Using the measurement of the patient's head circumference, the length,elasticity and thickness of headgear straps can be adjusted for aspecific patient to provide a secure, stable and comfortable patientinterface that is not too tight or too loose and requires little or nomanual adjustment by the patient. Additionally, the texture or surfacefinishing of headgear straps such as smoothness or roughness may beselected specific for a patient, for example, if they have facial hairor head hair. The profile, shape, arc length and flexibility of therigidizer arm 17250 may be selected specific for a patient. For example,a patient may have a wide face or a narrow face, and the rigidizer arm17250 is customised to exert minimal clamping pressure against thepatient's face and closely follow the contours of the patient's face,and also direct the headgear straps to pass optimally between thepatient's eyes and ears.

In some examples, optimisation of the length, elasticity and thicknessof headgear straps allows tightening or loosening the headgear strap(e.g., if length adjustable) or via elasticity if it is an elasticheadgear, to control the headgear tension force in the Frankforthorizontal plane for retaining the mask firmly against the patient'sface. The headgear tension force may customised depending on thepatient's comfort level and while ensuring that a minimum amount ofheadgear tension required to maintain a seal. Some patient's may prefera higher headgear tension force than is necessary to maintain a sealbecause the feeling of tightness of the headgear is reassuring andprovides greater confidence for these types of patients.

Additionally, the angle, position and orientation of slots 17135, whichaccept a corresponding tab or protrusion of rigidizer arm 17250 of theheadgear may be selected to create a custom headgear fit and customheadgear vector for each patient. As previously noted with reference toFIG. 17E, changing the angle, position and orientation of slot 17135changes the headgear vectors 17130 for a rigidizer arm 17250 of aheadgear and allows for the customisation of the headgear for superiorfit. In some examples, the rigidizer arm 17250 is customised to liebeneath every patient's cheek bone and optimally pass between thepatient's eyes and ears. Thus, by knowing the patient's anthropometricfeatures from the data collection 4300 step, the angle of the headgearvector may be tuned to achieve better performance. The angle of theheadgear vector may be determined relative to the Frankfort horizontal.An optimal angle for the headgear vector may improve comfort andstability of the patient interface because the angle for the headgearvector causes the sealing surface/sealing perimeter of the sealingelement 17300 to provide even pressure on against the patient's face(e.g. patient's nose and patient's upper lip). Without such optimisationof the headgear vector, tightening headgear straps may result in maskride up and therefore a less than optimum seal as the force to effectthe seal by the seal element 17300 is not evenly distributed.

In another example, an optimal angle for the headgear vector may includea bias to preload (typically a slightly higher angle), to take intoaccount tube torque in a downwardly direction. In other words, if thetube 17005 is pulled downward by a certain amount of force, thepreloading of the angle for the headgear vector is able to accommodatethis certain amount of force before mask stability is influenced.

5.11.7.5 Assembled Nare Cover

A fully assembled nare cover 17000 including frame 17200, rigidizer arm17250, sealing element 17300, headgear 17010 and delivery conduit 17005is shown by itself in FIGS. 17O-Q, and as donned in FIGS. 17R-T. Thepatient may couple sealing element 17300 to frame 17200 and don thecustomised nare cover 17000 using headgear 17010. As previouslydiscussed, rigidizer arms 17250 serve as a transition from frame 17200to headgear 17010 and redirect forces from the headgear so that frame17200 and sealing element 17300 are pushed towards the patient's face,resulting in a desirable seal of sealing element 17300 with thepatient's face. By using data acquired during data collection 4300, theangle, location and orientation of slots 17135 may be carefully selectedto ensure that the rigidizer arms 17250 to be received pass between themid-point between the patient's eyes and ear, or other desirableangles/positions/orientations to provide an optimal, stable andcomfortable seal for the small nare cover assembly.

Thus, the result of having such a nare cover is a customised mask, whichis as small as possible while being stable. Specifically, thecombination of superior contact of sealing element 17300 to thepatient's face, the sealing element 17300 interface with frame 17200 andthe use of L-shaped rigidizer arms 17250, as well as the customisationfrom data collection results in a small mask that is stable despite tubedrag, and body movements that occur under therapy. It will be understoodthat customisation has been discussed herein with reference to frame17200, vent holes 17240, sealing element 17300 and headgear 17010. Insome examples, a fully assembled custom nare cover 17000 includes one ormore customised elements. Additionally, customised and standardcomponents may be combined in various combinations to reduce cost (e.g.,a bespoke frame 17200 and a standard-sized sealing element 17300), andalso to offer various choices for the patient.

5.11.8 Complete Patient Interface Design Package 4550

With the patient interface and/or the headgear customised, completedpatient interface design package 4550 is the group of files whichincludes files for each of the individually designed patient interfacecomponents, ready for the manufacturing. Completed patient interfacedesign package 4550 may include data or information relating to any ofthe following: the list of components in the patient interface system(e.g., frame, intermediate structure, sealing element, headgear and/orany additional accessories such as elbows, tubes, headgear clips andsuch), CAD or data file for each component, the manufacturing techniquefor each component, the material(s) required for each component anddesigner and/or user comments. The patient's CAD file and/or photos (ifany) may be retained to support the selection of visually aestheticfeatures to stylise the patient interface according to the patient'spreference and taste.

5.11.9 Manufacturing 4600

Completed patient interface design package 4550 may be sent tomanufacturing 4600. There are many different manufacturing techniquesavailable for fabricating any of the components discussed above.Additionally, it will be understood that a combination of the techniquesdiscussed herein may be used to form different components of arespiratory patient interface.

The first group of techniques may be referred to as subtractivetechniques. In subtractive techniques, data may be collected andanalysed from patient skin 18050 and a completed patient interfacedesign package sent for manufacturing (FIG. 18A). A large blankcomponent 18010 may be modified to remove extra material 18012 such thatthe remaining portion 18014 forms the required custom component. In someexamples, large blank component 18010 is large enough to encompass mostpossible variations for custom component 18014. Several exemplarymethods under the subtractive techniques including machining using a CNCmachine to form the component out of a large block or generic patientinterface-shaped material. In some examples, a material such as siliconeor thermoplastic elastomer may be frozen into a rigid structure prior tomachining. A laser etching machine may also be used to remove materialfrom a larger block of material to create the component. This may beused to form rigid components or cut thin materials (foams, fabrics,silicone sheets, etc.). Abrasive chemicals may also be used to removematerials to create different finishes on the components. Some examplesinclude the use of acetone on plastics. Cutting tools, such cutting tool18060 shown in FIG. 18B, may also be used to stamp out components 18072,18074, 18076 from sheets of material 18070. Thus gel components 18072,silicone components 1804, and foam components 18076 may all be formed bychanging the type of sheet. This technique may be used, for example, tocreate headgear and sealing elements. Moreover, cutting tool 18060 mayhave curved cutting edges 18062 to form three-dimensional shapes.

A second group of techniques may be referred to as additive techniques.These may include SLS/SLA/FDM Printing, which involves printing theplastic or silicone components directly, thereby reducing waste materialfrom subtractive manufacturing. Components may be printed using a highquality 3D printers. Silicone components may also be fabricated viaadditive manufacturing through using a fast curing silicone grades.Silicone and elastomer printing machines may also be used. Whenavailable, patients may also be able to print their own patientinterfaces at home or at a local three-dimensional printer outlet. Thismethod is efficient and sustainable as there is almost no waste orscraps leftover from blanks. Textile spraying is also possible, whichinvolves spray a first material onto a second material. For example, aflocking material (felt, silk, textile blend etc.) may be sprayed ontothe intermediate component effectively creating a sealing element. Insome examples, the material may be sprayed through a multi axis CNCnozzle, mixed with glue/binding agent. Thus, varying numbers of layersmay be applied to all or parts of the sealing surface, forming acustomised sealing element.

Additionally, different manufacturing techniques may be used forcomponents of a mask assembly. For example, when forming a custom narecover, a frame and a sealing element may be formed of the same ordifferent techniques. Additionally, multiple techniques may be used toshape one component of a custom nare cover.

The frame 17200 may, for example, be formed by machining different-sizedmolded blanks. In at least some examples, a plurality of different-sizedblanks are molded to cover a broad spectrum of sizes. After dataacquisition, the blank closest to the intended mask design may beselected and the blank may be machined from the blank. Alternatively, anumber of different sized frames may be formed using size probabilitiesto mold a given volume of each size, and the frame of the closest sizemay be chosen for a patient.

Non-traditional machining techniques may also be applied to molded orcut blanks to form the frame and/or the sealing element. Thesetechniques may include electrical discharge machining, chemical etching,water jet cutting and/or laser cutting. In electrical dischargemachining, complex geometries of a component such as a frame or asealing element may be processed with a high degree of resolution. Byusing electrical discharge machining, a clean surface finish may beformed in delicate elements as no direct contact is made with theworking piece. In some examples, electrical discharge machining may beused to create vent holes or rigidizer receiving slots in a frame.Chemical etching may also be used to subtractively remove material andcreate a customised geometry with high resolution in a frame and/or asealing element. In some examples, chemical etching is desired whenmanufacturing fragile elements of the frame and/or sealing element asthere is no need for high heat which may damage a heat affected zone ofa component. Water jet cutting may also be used to shape a frame and/ora sealing element through a simple process with no heat affected zonesto create intricate geometries with high resolution. Laser cutting mayalso be used to create precise edges and cuts through a variety ofmaterials that may be suitable for a frame and/or a sealing element.

Additionally, the sealing element may be milled with a high speedabrasive cutting tool to shape the sealing element into the desiredshape. In at least some examples, the sealing element is frozen prior tothe milling process. Later, the sealing element is thawed or heated toroom temperature, if necessary. It will be understood that multipletechniques may be used in series or sequentially.

5.11.10 Tooling

For a more efficient method of manufacturing custom components thanadditive manufacturing, the moulding tools can be rapidly prototyped(e.g., 3D printed). In some examples, rapid three-dimensional printedtooling may provide a cost-effective method of manufacturing lowvolumes. Soft tools of aluminium and/or thermoplastics are alsopossible. Soft tools provide a low number of moulded parts and are costeffective compared to steel tools. As shown in FIG. 18C, a machine 18500may be used to create a soft tool 18502 to mould components 18504. Afteruse, soft tools 18502 may be melted down, recycled and made into adifferent shape for manufacturing a different custom patient interface.

Hard tooling may also be used during the manufacture of customcomponents. Hard tooling may be desirable in the event of favourablevolumes being produced. Hard tools may be made of various grades ofsteel or other materials for use during moulding/machining processes.The manufacturing process may also include the use of any combination ofrapid prototypes, soft and hard tools to make any of the components ofthe patient interface. The construction of the tools may also differwithin the tool itself, making use of any or all of the types of toolingfor example: one half of the tool, which may define more genericfeatures of the part may be made from hard tooling, while the half ofthe tool defining custom components may be constructed from rapidprototype or soft tooling. Combinations of hard or soft tooling are alsopossible.

FIGS. 18D illustrates an additional example of manufacturing usingchangeable tool inserts. In this method, a hard steel (or other suitablehard material for injection moulding) tool base is formed. In FIG. 18D,two portions 18510 and 18520 form the hard tool base. Interchangeabletool inserts 18522, 18524, 18526 are formed using, for example,aluminium or 3D printed plastic materials, each insert corresponding toa different patient's needs. Inserts 18522, 18524, 18526 may becustomised to each individual patient. Alternatively, multiple insertsmay be coupled to the same tool, so that different inserts may controldifferent sections of the patient interface e.g. nose bridge, mouthwidth, patient interface depth, etc.

Other manufacturing techniques may also include multi-shot injectionmoulding for patient interfaces having different materials within thesame component. For example, a patient interface cushion may includedifferent materials or softness grades of materials at different areasof the patient interface. Thermoforming (e.g., vacuum forming), whichinvolves heating sheets of plastic and vacuuming the sheets onto thetool mould and then cooling the sheets until it takes the shape of themould may also be used. This is a viable option for moulding componentsof the custom nare cover. In a yet another form, a material which may beinitially malleable may be used to produce a customised patientinterface frame (or any other suitable component such as a headgear orportions thereof, such as a rigidizer). A ‘male’ mould of the patientmay be produced using one or more techniques described herewithin, uponwhich a malleable ‘template’ component may be placed to shape thecomponent to suit the patient. Then, the customised component may be‘cured’ to set the component so that it would no longer be in amalleable state. One example of such a material may be a thermosettingpolymer, which is initially malleable until it reaches a particulartemperature (after which it is irreversibly cured), or a thermosofteningplastic (also referred to as thermoplastic), which becomes malleableabove a particular temperature. Custom fabric weaving/knitting/formingmay also be used. This technique is similar to three-dimensionalprinting processes except with yarn instead of plastic. The structure ofthe textile component may be knitted into any three-dimensional shapes,which are ideal for fabricating custom headgear.

Table A, below, illustrates some potential component and manufacturingcomponents. It will be understood that these combinations are merelyexemplary and that variations of these combinations are possible.

TABLE A Component Manufacturing Component Possible ManufacturingTechniques Frame Machining with laser etching (machining the componentfrom a larger generic moulded dummy patient interface and using laser orchemicals to etch the finer details). SLS/SLA Printing (directlyprinting the frame component). Rapid tooling (3D printed or aluminiumtooling to mould low volumes of components). Interchangeable toolinserts Thermoforming (along with rapid tooling and/or interchangeabletool inserts). Intermediate Rapid tooling Structure SLS/SLA printing(silicone, TPE or foam printers) Interchangeable tool InsertsCompression cutting (if the Intermediate component comprises of foam ortextile materials; cutting knives can be flexible and adjustable toachieve the different shapes, with robotic method of positioning theknives or materials). Multi-shot injection moulding (for differentmaterials within the same component) Sealing SLS/SLA Printing (silicone,TPE or foam Element printers) Rapid tooling Inter-changeable toolInserts Compression Cutting (if sealing element comprises a foam ortextile, or flocked foam (Bamberg) materials); cutting knives can beflexible and adjustable to achieve the different shapes, with roboticmethod of positioning the knives or materials. Multi-shot injectionmoulding Headgear Compression cutting (custom cut the templates for theheadgears; cutting knives may be flexible and adjustable to achieve thedifferent headgear shapes). Custom fabric weaving/knitting/forming (knitout the headgear template with control over the thickness, length andelasticity; form custom shapes by heating the fabrics into a malleablestate and them moulded onto tools).

5.11.11 Exemplary Embodiments

Table B, below, illustrates some exemplary embodiments of customisedrespiratory patient interfaces. Again, it will be understood that thesecombinations are merely exemplary and that variations of thesecombinations are possible.

TABLE B Custom Patient interface Embodiments # of Intermediate SealingEmbodiment Parts Frame Structure Element A 3 Custom Custom Custom B 3Custom Custom Standardised C 3 Custom Standardised Standardised D 3Custom Standardised Custom E 3 Standardised Standardised Custom F 3Standardised Custom Custom G 3 Standardised Custom Standardised H 2Standardised Custom I 2 Custom Standardised J 2 Custom Standardised K 1Custom

Embodiments A-K of Table B correspond to FIGS. 19A-K illustratingpatient interfaces 1900A-K. In FIG. 19A, patient interface 19000Aincludes three customised components, frame 19001, intermediatestructure 19002 and sealing element 19003. In this example, frame 19001is customised based on the patient's facial construct, and modified tomaximise comfort and stability while minimising the size of the part.This geometry would be mostly driven by the acquired three-dimensionalsurface data. Further input into the frame design may come from the userpreferences input such as: tube/elbow type and position, ventposition/type, colour etc. Intermediate structure 19002 is alsocustomised to provide a customised geometry or material composition thatprovides some finer tuning to the patient's facial construct bothgeometrically and interstitially. Customisation of intermediatestructure 19002 may be driven by both the 3D surface model and 2Dpressure map. Sealing element 19003 is also customised to provide themicro adjustments required to achieve a reliable and comfortable seal.Such finer adjustments may be in an effort to account for thedifferences between the relaxed and deformed state (e.g., thicker areasof soft material to account for areas of large deflection/movement inuse or in areas of discomfort). The data collection techniques and themodification algorithms discussed above may be used to create patientinterface 19000A.

Patient interface 19000B of FIG. 19B is generally the same as patientinterface 19000A, except that a standard sealing element 19003S is used.In this embodiment sealing element 19003S is a standard thin layer ofelastomer, foam, gel and/or tacky material that is easily attached tothe intermediate component in such a way that it does not crease/deformin an undesired manner and can be easily cut to each custom shape.

Patient interface 19000C of FIG. 19C is generally the same as patientinterface 19000B, except that a standard intermediate structure 19002Sis used. In this embodiment, several sizes of standard intermediatecomponents are used that suit different anthropometric ranges to providethe offset and compliance zones, similar to areas found in aconventional patient interface. Patient interface 19000D includes astandardised intermediate structure 19002S with a customised frame 19001and sealing element 19003 (FIG. 19D). In patient interface 19000E, onlysealing element 19003 is customised, while frame 19001S and intermediatestructure 19002S are standardised (FIG. 19E). In this embodiment,standardised frame 19001S may consist of one of several available sizesthat can interface with one of or all of several sizes of intermediatecomponents 19002S. While, this embodiment refers largely to standardisedframe geometry the user may still provide input for venting or colour ortube type/position.

In patient interface 1900F of FIG. 19F, only intermediate structure19002 is customised, while standardised frame 19001S and sealing element19003S are provided. Intermediate structure 19002 may provide an areathat provides the proper offsetting function, compliance region andcustomised macro and micro adjustments to suit individual facialgeometry, thus enabling a stable and comfortable customised platform towhich a sealing layer can be attached. In this example, intermediatestructure 19002 and sealing element 19003 may be provided as a singlepiece to the patient but consist of 2 different materials. The surfaceof intermediate structure 19002 that interfaces with the standardisedframe may have to take a geometry that enables fixation to the frame.This could be achieved by way of a surface blend, from the patient datadriven custom surfaces, to the required standard surfaces. In onevariation, patient interface 19000G is similar to patient interface19000F, except that sealing element 19003S is not customised in thisembodiment (FIG. 19G). In another variation, patient interface 1900Hincludes a unitary intermediate structure and sealing element 19012(FIG. 19H). Unitary intermediate structure and sealing element 19012 maybe moulded of a single material or formed of a multi-shot mould ofdiffering materials or through additive manufacturing using single ormultiple materials. Thus, unitary intermediate structure and sealingelement 19012 is formed as a single component designed and manufacturedas one, which then attaches to a standard or pre-existing frame 19001S.Patient interface 190001 provides a customised unitaryframe/intermediate structure 19011 with a standardised sealing element19003S (FIG. 19I).

In FIG. 19J, patient interface 19000J is formed having a customisedframe 19001 and a standardised sealing element 19003S. This embodimenteliminates an intermediate structure. Instead, the customised frame19001 functions as both a frame and an intermediate structure. Finally,in FIG. 19K, a fully-customised single component 19100 patient interface19000K is shown. Single component 19100 may be formed of a singlematerial (e.g., Mirage FX, Nano) or a combination of any of thematerials discussed above. In some examples, patient interface 19000K isformed of a single shot of a single material in a custom tool.Alternatively, patient interface 19000K may be produced using multiplematerials, using multi-shot injection moulding in a custom tool, orproduced directly via rapid manufacturing techniques that includemultiple materials with different properties 3D printed using eithermulti-head FDM or multi-material photopolymer printing or similar.

5.11.12 Distribution 4700

In order to provide the best benefit to the patient and to ensure thatadequate sealing is accomplished, for example, between a frame andsealing element as described with respect to a custom nare cover,information relating to a mask may be recorded and stored on a centralserver. Such information may be entered when a patient opens an onlineaccount and creates a patient profile, and include data relating to aninitial facial geometry scan, designed custom mask geometry, personalaesthetic preferences or flow generator preferences, and the like. Theonline account may hold the patient's custom mask information andtherefore can act as a platform where the custom mask details like thecurrent patient facial geometry can be updated and also a platform wherepatients may order more of their custom masks and therefore optimise thebenefits of their custom mask, keeping up compliance of that patientwith the desirable therapy.

Along with this online account a patient ID number or sequence (e.g., abarcode) may be assigned to the patient. The patient ID number may belabelled onto the custom mask to give the product identification, sothat each mask may be traced back to their respective owners forreturns, optimisation and the like. For patient purchasing a maskproduct in person, the ID number or sequence may be scanned and maskcomponents may be ordered in through traditional retail locations oronline. In at least some example, the ID number or sequence may includeat least one of a barcode sequence, or a symbol (numeric, alphabetical,etc.) that is pad printed, three-dimensional colour printed, orgeometrically printed onto a mask component. A radiofrequency ID chipmay also be embedded in a mask, which may be three-dimensionallyprinter-embedded or inserted after manufacturing. Additionally, physicalcopies of a customised mask component (e.g., a frame) may be stored, andmay later be scanned if replenishments are desired.

5.12 Other Remarks

A portion of the disclosure of this patent document contains materialwhich is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in the Patent and TrademarkOffice patent file or records, but otherwise reserves all copyrightrights whatsoever.

Unless the context clearly dictates otherwise and where a range ofvalues is provided, it is understood that each intervening value, to thetenth of the unit of the lower limit, between the upper and lower limitof that range, and any other stated or intervening value in that statedrange is encompassed within the technology. The upper and lower limitsof these intervening ranges, which may be independently included in theintervening ranges, are also encompassed within the technology, subjectto any specifically excluded limit in the stated range. Where the statedrange includes one or both of the limits, ranges excluding either orboth of those included limits are also included in the technology.

Furthermore, where a value or values are stated herein as beingimplemented as part of the technology, it is understood that such valuesmay be approximated, unless otherwise stated, and such values may beutilized to any suitable significant digit to the extent that apractical technical implementation may permit or require it.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this technology belongs. Although any methods andmaterials similar or equivalent to those described herein can also beused in the practice or testing of the present technology, a limitednumber of the exemplary methods and materials are described herein.

When a particular material is identified as being preferably used toconstruct a component, obvious alternative materials with similarproperties may be used as a substitute. Furthermore, unless specified tothe contrary, any and all components herein described are understood tobe capable of being manufactured and, as such, may be manufacturedtogether or separately.

It must be noted that as used herein and in the appended claims, thesingular forms “a”, “an”, and “the” include their plural equivalents,unless the context clearly dictates otherwise.

All publications mentioned herein are incorporated by reference todisclose and describe the methods and/or materials which are the subjectof those publications. The publications discussed herein are providedsolely for their disclosure prior to the filing date of the presentapplication. Nothing herein is to be construed as an admission that thepresent technology is not entitled to antedate such publication byvirtue of prior invention. Further, the dates of publication providedmay be different from the actual publication dates, which may need to beindependently confirmed.

Moreover, in interpreting the disclosure, all terms should beinterpreted in the broadest reasonable manner consistent with thecontext. In particular, the terms “comprises” and “comprising” should beinterpreted as referring to elements, components, or steps in anon-exclusive manner, indicating that the referenced elements,components, or steps may be present, or utilized, or combined with otherelements, components, or steps that are not expressly referenced.

The subject headings used in the detailed description are included onlyfor the ease of reference of the reader and should not be used to limitthe subject matter found throughout the disclosure or the claims. Thesubject headings should not be used in construing the scope of theclaims or the claim limitations.

Although the technology herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thetechnology. In some instances, the terminology and symbols may implyspecific details that are not required to practice the technology. Forexample, although the terms “first” and “second” may be used, unlessotherwise specified, they are not intended to indicate any order but maybe utilised to distinguish between distinct elements. Furthermore,although process steps in the methodologies may be described orillustrated in an order, such an ordering is not required. Those skilledin the art will recognize that such ordering may be modified and/oraspects thereof may be conducted concurrently or even synchronously.

It is therefore to be understood that numerous modifications may be madeto the illustrative embodiments and that other arrangements may bedevised without departing from the spirit and scope of the technology.

6 REFERENCE NUMERALS

outer chamber 10 patient 1000 bed partner 1100 virtual portal 1400 rptdevice 1500 third strap 1514 air circuit 1600 humidifier 1700 nare cover1700 silicone component 1804 edition published 2011 patient interface3000 patient interface sealing surface 3100 plenum chamber 3200 headgearsystem 3300 vent 3400 forehead support 3500 swivel 3510 socket 3520connection port 3600 iso 3744 asphyxia valve 3800 patient interfacecustomisation method 4000 remote external communication network 4282local external communication network 4284 remote external device 4286local external device 4288 display driver 4292 display 4294 patient datacollection 4300 step 4300 relaxed state data collection 4301 deformedstate data collection 4302 pressure mapping 4303 user input 4304processing module 4310 pressure compensation algorithm 4312 vent flowrate calculation algorithm 4314 leak flow rate algorithm 4316respiratory flow rate algorithm 4318 phase determination algorithm 4321target ventilation determination algorithm 4328 data processing step4400 post processing step 4401 experienced pressure 4402 specificfeature processing 4403 patient preference 4404 output data package 4450geometric surface model design package 4451 pressure map design package4452 patient interface design 4500 patient interface design package 4550manufacturing 4600 distribution 4700 final product 4700 laser scanningsystem 5000 laser 5001 len 5002 sensor 5003 object 5050 humidifierreservoir 5110 humidifier reservoir dock 5130 temperature sensor 5216camera 6001 camera 6002 display 6003 patient 6050 data collection system7000 rod 7001 force sensor 7002 processor 7003 patient's face 7050 castmaterial 7060 mould 7065 scanner 7070 tooling 7075 rigid deformingdevice 8001 face deforming device 8001 camera 8002 device 8010 dummypatient interface 8020 pressure film 8021 tactile pressure film sensor8021 processor 8022 pressure map 8030 patient's skin 8050 nasal bridge8051 surface 8055 patient 9000 nasian 9003 nasal 9004 philtrum 9005 lipfold 9008 mental eminence 9009 suborbital 9015 inferior malar 9016lateral nostril 9017 labial ridge 9018 canina 9019 sub canina 9020 nosepatient interface 10000 first input 10010 corresponding padding 10012second input 10020 corresponding gel portion 10022 third input 10030beard patch 10032 patient 10100 patient 10200 patient's head 10300patient interface 10401 patient interface 11000 frame 11001 intermediatestructure 11002 sealing element 11003 custom sealing element 11003patient interface frame 12010 custom frame assembly 12020 frame 12030standardised frame 12040 frame 12041 standardised frame 12042 patient'sface 12050 interlock system 12060 customised component 12070intermediate structure 13010 first component 13012 second component13014 frame 13040 frame 13042 patient 13050 sealing element 13510optimal sealing element 13510 sealing element 13511 sealing element13520 sealing element 13522 patient's face 13550 patient interface 13552cushion 14102 inner cushion component 14104 outer barrier 14106 chamber14108 chamber material 14110 rib 14112 optional internal barriermembrane 14512 mask interconnect component 14516 adhesive 14518 optionalclip 14520 soft springing foam 14560 elastomer 14562 foam ball 14564 gel14566 cap portion 14672 mask frame 14690 channel 14692 ridge 14694 gasport 14696 first layer 14802 second layer 14804 layer 14806 bottom end14902 top end 14904 first layer 14912 second layer 14914 third layer14916 fourth “hollow” layer 14918 frangible seal 14922 tab 14924 patientinterface 15002 headgear 15004 first strap 15010 second strap 15012third strap 15014 neck attachment 15040 crown attachment 15042 patient15050 nose bridge anchor point 16002 mouth anchor point 16004 mouthanchor point 16006 ear anchor point 16008 patient 16050 patientinterface 16060 sealing element 16062 precise sealing element 16062structure 16070 compliant joint feature 16080 patient's head 16100 skull16102 patient's skin 16104 nose 16106 patient interface's associatedheadgear 16108 patient interface 16110 bed pillow 16120 suborbital 16205alar angle 16210 nose corner 16215 nose middle 16220 width 16225 secondportion 16246 first condition 16300 second condition 16305 patient 16350headgear 16352 patient interface 16400 conduit 16401 sealing element16402 headgear 16403 first portion 16404 second portion 16406 patientinterface 16410 conduit 16411 sealing element 16412 headgear 16413 crownstrap 16414 second portion 16416 buckle 16419 patient interface 16420conduit 16421 sealing element 16422 headgear 16423 first portion 16424second portion 16426 wireform 16428 nare cover 17000 delivery conduit17005 headgear 17010 marker 17100 surface 17102 elliptical position17120 headgear vector 17130 slot 17135 frame 17200 inner wall 17210 sealreceiving surface 17220 aperture 17230 vent hole 17240 rigidizer arm17250 first end 17252 second end 17254 sealing element 17300 foam layer17302 adhesive PSA backing 17304 single flat profile 17310 dimensionalmodel 17310 first surface 17350 second surface 17355 large blankcomponent 18010 extra material 18012 custom component 18014 patient18050 tool 18060 curved cutting edge 18062 material 18070 component18072 component 18074 component 18076 third layer 18106 machine 18500soft tool 18502 component 18504 portion 18510 portion 18520interchangeable tool insert 18522 interchangeable tool insert 18524interchangeable tool insert 18526 frame 19001 intermediate structure19002 sealing element 19003 unitary frame/intermediate structure 19011sealing element 19012 single component 19100 rpt device 40000 externalhousing 40100 upper portion 40120 portion 40140 panel 40150 chassi 40160handle 40180 pneumatic block 40200 pneumatic component 41000 air filter41100 inlet air filter 41120 outlet air filter 41140 inlet muffler 41220outlet muffler 41240 pressure generator 41400 blower 41420 brushless DCmotor 41440 air circuit 41700 air circuit 41710 supplemental oxygen41800 electrical component 42000 pcba 42020 board Assembly PCBA 42020power supply 42100 present technology power supply 42100 input device42200 central controller 42300 clock 42320 therapy device controller42400 protection circuit 42500 memory 42600 transducer 42700 pressuretransducer 42720 flow rate sensor 42740 motor speed transducer 42760data communication interface 42800 output device 42900 algorithm 43000therapy engine module 43200 phase determination algorithm 43210 waveformdetermination 43220 ventilation determination 43230 inspiratory flowlimitation determination 43240 apnea/hypopnea determination 43250 snoredetermination 43260 airway patency determination 43270 targetventilation determination algorithm 43280 target ventilationdetermination 43280 therapy parameter determination algorithm 43290therapy control module 43300 method 45000 step 45200 step 45300 step45400 step 45500 step 45600 humidifier 50000 humidifier outlet 50040humidifier base 50060 humidifier reservoir 51100 conductive portion51200 reservoir dock 51300 locking lever 51350 water level indicator51500 humidifier transducer 52100 air pressure sensor 52120 flow ratetransducer 52140 temperature transducer 52160 humidity sensor 52180heating element 52400 humidifier controller 52500 central humidifiercontroller 52510 heating element controller 52520 air circuit controller52540 patient interface 161100 central controller 423000 therapy enginemodule 432000 elastic inner layer 16417a inner layer 16417a outer layer16417b location 16A location 16B location 16C patient interface 19000Apatient interface 19000B patient interface 19000C patient interface19000D patient interface 19000E patient interface 19000F patientinterface 19000G patient interface 19000I patient interface 19000Jpatient interface 19000K standard frame 19001S standard intermediatestructure 19002S standard sealing element 19003S patient interface 1900Fpatient interface 1900H first diagonal force T1 second force T2 thirdforce T3

1. A method of manufacturing a patient interface for sealed delivery ofa flow of air at a continuously positive pressure with respect toambient air pressure to an entrance to a patient's airways, the methodcomprising: collecting anthropometric data of a patient's face;identifying anticipated considerations from the collected anthropometricdata for use of the patient interface; processing the collectedanthropometric data to provide a transformed data set based on theanticipated considerations, the transformed data set corresponding to atleast one customised patient interface component; and modelling at leastone patient interface component based on the transformed data set. 2.The method of claim 1, wherein collecting anthropometric data comprisescollecting relaxed state data of a patient's face.
 3. The method ofclaim 2, wherein the relaxed state data is collected by contactlessmethods.
 4. The method of claim 3, wherein contactless methods is anyone from a group consisting of: laser scanning and passive stereophotogrammetry.
 5. The method of claim 2, wherein the relaxed state datais collected by contact methods.
 6. The method of claim 5, wherein thecontact methods include use of a memory material or mechanical rods. 7.The method of claim 6, wherein each mechanical rod has a patient facecontacting end portion with a predetermined curved shape.
 8. The methodof claim 6, wherein the mechanical rods are arranged in an array andnon-uniformly distributed in the array to obtain a varying resolution ofthe collected anthropometric data.
 9. The method of claim 6, wherein themechanical rods travel in different directions.
 10. The method of claim1, wherein collecting anthropometric data comprises collecting deformedstate data of a patient's face based on the patient's facial geometryunder a force.
 11. The method of claim 10, wherein the deformed statedata is obtained at a plurality of deformations.
 12. The method of claim10, wherein the force comprises at least one of a gravitational force oran applied force.
 13. The method of claim 5, wherein collectinganthropometric data comprises placing the patient's face against aplastically deforming device and collecting the deformed state databased on a resulting deformation of the deforming device.
 14. The methodof claim 13, wherein the plastically deforming device is re-used as apatient interface component.
 15. The method of claim 5, whereincollecting anthropometric data comprises placing the patient's faceagainst a deforming device to provide a deformed state and imaging thepatient's face in the deformed state.
 16. The method of claim 1, furthercomprising collecting pressure data experienced on the patient's faceduring use of a patient interface.
 17. The method of claim 10, whereincollecting pressure data comprises placing the patient's face against amask blank having a tactile pressure film sensor.
 18. The method ofclaim 1, wherein the collected anthropometric data comprises relaxedstate data, and further comprising the step of simulating deformed statedata based on the relaxed state data and known tissue properties. 19.The method of claim 18, wherein known tissue properties include any onefrom a group consisting of: soft tissue thickness, modulus data based onforce, deflection, modulus and thickness, soft tissue thickness ratioinformation, and body mass index (BMI).
 20. The method of claim 1,wherein the collected anthropometric data comprises relaxed state data,and further comprising the step of simulating pressure data based on therelaxed state data and known tissue properties.
 21. The method of claim1, further comprising gathering patient input relating to at least oneof functionality, comfort and aesthetics.
 22. The method of claim 21,wherein gathering patient input comprises providing a rendering of atleast one possible patient interface on the patient.
 23. The method ofclaim 1, wherein identifying anticipated considerations comprisesidentifying specific areas of the face with respect to at least one ofpressure sensitivity, pressure compliance, shear sensitivity and shearcompliance.
 24. The method of claim 1, wherein identifying anticipatedconsiderations comprises identifying at least one of facial hair,hairstyle and facial landmarks from the collected anthropometric data.25. The method of claim 1, wherein processing the collectedanthropometric data comprises providing a uniform offset distance aroundone feature of the patient's face, and modelling at least one componentcomprises forming a frame having the uniform offset distance.
 26. Themethod of claim 1, wherein processing the collected anthropometric datacomprises providing variable offset distances around features of thepatient's face, and modelling at least one component comprises forming aframe having the variable offset distances.
 27. The method of claim 1,wherein processing the collected anthropometric data comprises providinga first surface in a sagittal plane that blends a number of selectedsurfaces of the patient's face, and modelling at least one componentcomprises forming a frame having the first surface.
 28. The method ofclaim 1, wherein processing the collected anthropometric data comprisesproviding a second surface in a coronal plane that blends a number ofselected surfaces of the patient's face, and modelling at least onecomponent comprises forming a frame having the second surface.
 29. Themethod of claim 1, wherein modelling at least one component comprisesforming an intermediate structure having microfit and macrofitcomponents that are chosen based on the transformed data set.
 30. Themethod of claim 1, wherein processing the collected anthropometric datacomprises selecting a predetermined sealing surface area, and modellingat least one component comprises forming a sealing element having adesired sealing surface area.
 31. The method of claim 30, furthercomprising scaling a volume of a modelled patient interface by reducingan interior volume, defined between the patient's face and the patientinterface, by about 1% to about 50%.
 32. The method of claim 31, whereinscaling a volume comprises altering a distance of a frame from thepatient's nose.
 33. The method of claim 1, wherein the collection ofanthropometric data of the patient's face is performed when the patientis in a supine position or in an upright position.
 34. A patientinterface for sealed delivery of a flow of air at a continuouslypositive pressure with respect to ambient air pressure to an entrance tothe patient's airways comprising: at least one component modelled fromcollected patient data that has been transformed based on known tissueproperties.
 35. A patient interface for sealed delivery of a flow of airat a continuously positive pressure with respect to ambient air pressureto an entrance to the patient's airways comprising: a frame forproviding an offset distance from the patient's airways; an intermediatestructure coupleable to the frame; and a sealing element coupleable tothe intermediate structure and in contact with the patient's face;wherein at least one of the frame, the intermediate structure and thesealing element is modelled from collected patient data that has beentransformed based on anticipated considerations.
 36. The patientinterface of claim 35, further comprising a positioning and stabilisingstructure to maintain the sealing element in sealing contact with anarea surrounding an entrance to the patient's airways while maintaininga therapeutic pressure at the entrance to the patient's airways.
 37. Thepatient interface of claim 35, wherein the frame includes a firstsurface in a sagittal plane that blends a number of selected surfaces ofthe patient's face.
 38. The patient interface of claim 35, wherein theframe includes a second surface in a coronal plane that blends a numberof selected surfaces of the patient's face.
 39. The patient interface ofclaim 35, wherein the frame includes a uniform offset distance aroundone feature of the patient's face.
 40. The patient interface of claim35, wherein the frame includes variable offset distances around featuresof the patient's face.
 41. The patient interface of claim 35, whereinthe intermediate structure includes microfit and macrofit componentsconfigured based on data that has been transformed.
 42. The patientinterface of claim 35, wherein the sealing element includes a desiredsealing surface area in a range of about 1 cm2 to about 30 cm2.
 43. Apatient interface for delivery of a supply of pressurised air orbreathable gas to an entrance to the patient's airways comprising: aframe assembly having walls and configured to be disposed over nares ofthe patient and extending along a generally elliptical path that coversouter peripheries of the nares including alar sidewalls and a portion ofa columella of the patient, the frame assembly defining a plenum chamberbetween its walls and the patient's skin; and a sealing element capableof forming a seal against skin that surrounds both nares of the patientwithout being partially located inside the patient's nose, the sealingelement being less rigid than the frame assembly and having an adhesiveon at least one side of the sealing element, the sealing element beingcoupleable to an anterior wall of the frame assembly.
 44. The patientinterface of claim 43, wherein the sealing element includes a foam layerlaminated onto a pressure-sensitive adhesive layer.
 45. The patientinterface of claim 43, wherein the sealing element includes an adhesiveon a patient-contacting side.
 46. The patient interface of claim 43,wherein the sealing element includes an adhesive on both apatient-contacting side and a frame contacting side.
 47. The patientinterface of claim 43, wherein the frame assembly includes a pluralityof vent holes.
 48. The patient interface of claim 47, wherein theplurality of vent holes includes a number of vent holes that areproportional to a measure of dead space.
 49. The patient interface ofclaim 43, wherein the frame assembly includes a plurality of slots foraccepting rigidizer arms that couple with a headgear.
 50. The patientinterface of claim 43, wherein the plenum chamber has a volume that isapproximately a multiplier between 1 to 2 times of the patient's nose.51. A patient interface for sealed delivery of a flow of air at acontinuously positive pressure with respect to ambient air pressure toan entrance to the patient's airways comprising: a mask assembly; asealing element coupleable to the mask assembly and in contact with thepatient's face; and a positioning and stabilising structure, coupled tothe mask assembly, the positioning and stabilising structure beingconfigured to maintain the sealing element in sealing contact with anarea surrounding an entrance to the patient's airways while maintaininga therapeutic pressure at the entrance to the patient's airways; whereinat least one of the mask assembly, the sealing element and thepositioning and stabilising structure is configured to compensate forskin movement and deformation.
 52. The patient interface of claim 51,wherein the positioning and stabilising structure is configured tocompensate for longitudinal skin sheer of between approximately 1 mm andapproximately 50 mm with respect to a longitudinal axis of the patient'sface.
 53. The patient interface of claim 51, wherein the positioning andstabilising structure is configured to compensate for lateral skin sheerof between approximately 1 mm and approximately 30 mm with respect to alongitudinal axis of the patient's face.
 54. The patient interface ofclaim 51, wherein the positioning and stabilising structure isconfigured to compensate for nare angle deflection of betweenapproximately 1 degree and 30 degrees.
 55. The patient interface ofclaim 51, wherein the positioning and stabilising structure isconfigured to compensate for an upward movement of corners and middle ofa nose of a maximum of approximately 9 mm and approximately 4 mm,respectively.
 56. The patient interface of claim 51, wherein thepositioning and stabilising structure is configured to compensate for anincrease in a width of the patient's nose of between approximately 1 mmand approximately 4 mm.
 57. The patient interface of claim 51, whereinthe positioning and stabilising structure is configured to compensatefor a cheek bulge from a first condition to a second condition, thefirst condition and second condition being spaced by betweenapproximately 1 mm and 10 mm.
 58. The patient interface of claim 51,wherein the positioning and stabilising structure includes a firstportion and a second portion, the first portion and the second portionbeing configured to compensate for perturbations such that the sealingelement remains in contact with the patient's face when a force of up to10 Newtons is applied to a portion of the positioning and stabilisingstructure.
 59. The patient interface of claim 58, wherein the firstportion is formed of a non-elastic material and the second portion isformed of an elastic material.
 60. The patient interface of claim 51,wherein the positioning and stabilising structure includes a firstportion and a second portion, at least one of the first portion and thesecond portion having an elastic material configured to compensate forperturbations such that the sealing element remains in contact with thepatient's face when a force of up to 10 Newtons is applied to thepositioning and stabilising structure.
 61. The patient interface ofclaim 51, wherein the positioning and stabilising structure includes afirst portion, a second portion, and a path portion coupled to the firstportion and coextensive with the second portion, the second portionbeing capable of translation along the path portion.
 62. The patientinterface of claim 61 wherein the path portion comprises a wireframe.